t/t9601-cvsimport-vendor-branch.sh: Add a PERL prerequisite

Change this test to declare a PERL prerequisite. These tests use the
-p switch, so they implicitly depend on Perl code, but nothing was
declaring this.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9601-cvsimport-vendor-branch.sh

@@ -34,50 +34,52 @@
 test_description='git cvsimport handling of vendor branches'
 . ./lib-cvs.sh
 
-CVSROOT="$TEST_DIRECTORY"/t9601/cvsroot
-export CVSROOT
+test_expect_success PERL 'setup CVSROOT' '
+	CVSROOT="$TEST_DIRECTORY"/t9601/cvsroot &&
+	export CVSROOT
+'
 
-test_expect_success 'import a module with a vendor branch' '
+test_expect_success PERL 'import a module with a vendor branch' '
 
 	git cvsimport -C module-git module
 
 '
 
-test_expect_success 'check HEAD out of cvs repository' 'test_cvs_co master'
+test_expect_success PERL 'check HEAD out of cvs repository' 'test_cvs_co master'
 
-test_expect_success 'check master out of git repository' 'test_git_co master'
+test_expect_success PERL 'check master out of git repository' 'test_git_co master'
 
-test_expect_success 'check a file that was imported once' '
+test_expect_success PERL 'check a file that was imported once' '
 
 	test_cmp_branch_file master imported-once.txt
 
 '
 
-test_expect_failure 'check a file that was imported twice' '
+test_expect_failure PERL 'check a file that was imported twice' '
 
 	test_cmp_branch_file master imported-twice.txt
 
 '
 
-test_expect_success 'check a file that was imported then modified on HEAD' '
+test_expect_success PERL 'check a file that was imported then modified on HEAD' '
 
 	test_cmp_branch_file master imported-modified.txt
 
 '
 
-test_expect_success 'check a file that was imported, modified, then imported again' '
+test_expect_success PERL 'check a file that was imported, modified, then imported again' '
 
 	test_cmp_branch_file master imported-modified-imported.txt
 
 '
 
-test_expect_success 'check a file that was added to HEAD then imported' '
+test_expect_success PERL 'check a file that was added to HEAD then imported' '
 
 	test_cmp_branch_file master added-imported.txt
 
 '
 
-test_expect_success 'a vendor branch whose tag has been removed' '
+test_expect_success PERL 'a vendor branch whose tag has been removed' '
 
 	test_cmp_branch_file master imported-anonymously.txt