Fix uses of uninitialized values in the http-parser backend, a bug introduced
in libgit2 1.8.1:

  https://github.com/libgit2/libgit2/pull/6870

This code is exercised by 'tests/proxy.scm' in Guile-Git.

diff --git a/src/libgit2/transports/httpparser.c b/src/libgit2/transports/httpparser.c
index 50ba6d2e0..c19499b84 100644
--- a/src/libgit2/transports/httpparser.c
+++ b/src/libgit2/transports/httpparser.c
@@ -71,6 +71,7 @@ size_t git_http_parser_execute(
 {
 	struct http_parser_settings settings_proxy;
 
+	settings_proxy.on_status = NULL;
 	settings_proxy.on_message_begin = parser->settings.on_message_begin ? on_message_begin : NULL;
 	settings_proxy.on_url = parser->settings.on_url ? on_url : NULL;
 	settings_proxy.on_header_field = parser->settings.on_header_field ? on_header_field : NULL;
@@ -78,6 +79,8 @@ size_t git_http_parser_execute(
 	settings_proxy.on_headers_complete = parser->settings.on_headers_complete ? on_headers_complete : NULL;
 	settings_proxy.on_body = parser->settings.on_body ? on_body : NULL;
 	settings_proxy.on_message_complete = parser->settings.on_message_complete ? on_message_complete : NULL;
+	settings_proxy.on_chunk_header = NULL;
+	settings_proxy.on_chunk_complete = NULL;
 
 	return http_parser_execute(&parser->parser, &settings_proxy, data, len);
 }
commit/gnu/packages/pep.scm?id=895de955ae7c1640add70c8d2354942e36eccdf6'>commit</a><a href='/guix/diff/gnu/packages/pep.scm?id=895de955ae7c1640add70c8d2354942e36eccdf6'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/pep.scm'>
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<div class='path'>path: <a href='/guix/log/?id=895de955ae7c1640add70c8d2354942e36eccdf6'>root</a>/<a href='/guix/log/gnu?id=895de955ae7c1640add70c8d2354942e36eccdf6'>gnu</a>/<a href='/guix/log/gnu/packages?id=895de955ae7c1640add70c8d2354942e36eccdf6'>packages</a>/<a href='/guix/log/gnu/packages/pep.scm?id=895de955ae7c1640add70c8d2354942e36eccdf6'>pep.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/pep.scm?id=895de955ae7c1640add70c8d2354942e36eccdf6&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-06-26 22:10:38 -0400'>2022-06-26</span></td><td><a href='/guix/commit/gnu/packages/pep.scm?id=ed210c1b8ff95003645499a4b48279a68c4685cf'>gnu: python-setuptools-scm: Move to (gnu packages python-build).</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/python-xyz.scm (python-setuptools-scm): Move from here...
* gnu/packages/python-build.scm (python-setuptools-scm): ... to here.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-02-15 20:44:21 +0100'>2022-02-15</span></td><td><a href='/guix/commit/gnu/packages/pep.scm?id=3f9c432bfb7ded3c0c9698132ec7eb01d38d8ad9'>gnu: pep-engine: Simplify inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/pep.scm (pep-engine): Simplify inputs.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2022-02-15 20:44:21 +0100'>2022-02-15</span></td><td><a href='/guix/commit/gnu/packages/pep.scm?id=1bd1f42a31a970489583682434cda706b0269c26'>gnu: Remove unneeded uses of 'libiconv'.</a><span class='msg-avail'>...<span class='msg-tooltip'>iconv is part of glibc, there is no need to add it as input.

* gnu/packages/accessibility.scm (brltty)[inputs]: Remove LIBICONV.
* gnu/packages/compression.scm (innoextract)[inputs]: Likewise.
* gnu/packages/haskell-apps.scm (darcs)[inputs]: Likewise.
* gnu/packages/kde-multimedia.scm (k3b)[inputs]: Likewise.
* gnu/packages/linphone.scm (liblinphone)[inputs]: Likewise.
* gnu/packages/mail.scm (mailutils)[inputs]: Likewise.
* gnu/packages/maths.scm (libqalculate)[inputs]: Likewise.
* gnu/packages/pep.scm (pep-engine)[inputs]: Likewise.
* gnu/packages/vim.scm (neovim)[inputs]: Likewise.
* gnu/packages/wget.scm (wget2)[inputs]: Likewise.
* gnu/packages/telegram.scm (telegram-desktop)[inputs]: Likewise.
* gnu/packages/video.scm (transcode)[native-inputs]: Likewise.
</span></span></td><td>Marius Bakke</td></tr>