Boolean pixel values are no longer supported in VTK 9.2.

diff --git a/addons/vtk/test_vtkimage.cc b/addons/vtk/test_vtkimage.cc
--- a/addons/vtk/test_vtkimage.cc
+++ b/addons/vtk/test_vtkimage.cc
@@ -206,7 +206,7 @@ BOOST_AUTO_TEST_CASE_TEMPLATE( test_mhd_write_read, T, type_mhd )
        unlink(zrawfilename.str().c_str());
 }
 
-#if  VTK_MAJOR_VERSION >= 7
+#if  VTK_MAJOR_VERSION >= 7 && VTK_MAJOR_VERSION < 9
 BOOST_AUTO_TEST_CASE( test_simple_write_read_bool )
 {
        C3DBounds size(2, 3, 4);
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<div class='path'>path: <a href='/guix/log/?id=83e84ed4628e834516e52dcf8d40c6d2afada5e5'>root</a>/<a href='/guix/log/etc?id=83e84ed4628e834516e52dcf8d40c6d2afada5e5'>etc</a>/<a href='/guix/log/etc/time-travel-manifest.scm?id=83e84ed4628e834516e52dcf8d40c6d2afada5e5'>time-travel-manifest.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/etc/time-travel-manifest.scm?id=83e84ed4628e834516e52dcf8d40c6d2afada5e5&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-09-09 19:36:05 +0200'>2023-09-09</span></td><td><a href='/guix/commit/etc/time-travel-manifest.scm?id=a4c35c607cfd7d6b0bad90cfcc46188d489e1754'>time-travel-manifest: Comment out versions older than 1.3.0 for now.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/time-travel-manifest.scm (%release-commits): Comment out revisions
older than 1.3.0.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-09-09 19:33:31 +0200'>2023-09-09</span></td><td><a href='/guix/commit/etc/time-travel-manifest.scm?id=d4bd5bc799e2face0b30bdb3a6ec3c347c0d1e22'>time-travel-manifest: Add 1.4.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/time-travel-manifest.scm (%release-commits): Add 1.4.0.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-08-17 15:42:56 +0200'>2022-08-17</span></td><td><a href='/guix/commit/etc/time-travel-manifest.scm?id=845c841e21379e64a4215ee6d3d60da343e7fb93'>time-travel-manifest: Use a separate cache per system.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/time-travel-manifest.scm (&lt;guix-instance-compiler&gt;): Use a separate
cache per system so that parallel system evaluations do no step on each
other's toes.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2022-07-10 23:57:14 +0200'>2022-07-10</span></td><td><a href='/guix/commit/etc/time-travel-manifest.scm?id=5d0437ea8ce0147b47b9df866fa2413b48f71a1a'>time-travel-manifest: Use a separate Git checkout cache.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/time-travel-manifest.scm (guix-instance-compiler): Parameterize
%REPOSITORY-CACHE-DIRECTORY.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-07-08 23:58:11 +0200'>2022-07-08</span></td><td><a href='/guix/commit/etc/time-travel-manifest.scm?id=e80f0cda96181d90604c44f69094f2499036b3f6'>etc: Add 'time-travel-manifest.scm'.</a><span class='msg-avail'>...<span class='msg-tooltip'>This manifest makes it easy to test travels from the current revision
back to the revision of a past Guix release.

Suggested by zimoun &lt;zimon.toutoune@gmail.com&gt;.

* etc/time-travel-manifest.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.
</span></span></td><td>Ludovic Courtès</td></tr>