t9143: do not fail when unhandled.log.gz is not created

Do not depend on internal implementation details of svn,
which right now uses perl to create a .gz file.
So this test case will even work in the future,
when svn changes its implementation.

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Acked-by: Eric Wong <normalperson@yhbt.net>

t/t9143-git-svn-gc.sh

@@ -37,13 +37,11 @@ test_expect_success 'git svn gc runs' 'git svn gc'
 
 test_expect_success 'git svn index removed' '! test -f .git/svn/refs/remotes/git-svn/index'
 
-if perl -MCompress::Zlib -e 0 2>/dev/null
+if test -r .git/svn/refs/remotes/git-svn/unhandled.log.gz
 then
 	test_expect_success 'git svn gc produces a valid gzip file' '
 		 gunzip .git/svn/refs/remotes/git-svn/unhandled.log.gz
 		'
-else
-	say "# Perl Compress::Zlib unavailable, skipping gunzip test"
 fi
 
 test_expect_success 'git svn gc does not change unhandled.log files' '