t9200: make test "set -e" clean

In order to catch mistakes like misspelling "test_expect_success",
we would like to eventually be able to run our test suite with the
"-e" option on.

This test uses the usual pattern, where it

	cmd ...
	if test $? ...

expects cmd to be allowed to fail freely and we can act on its exit
status, which is not possible under "set -e".  Rewrite it using the
common pattern:

	status=0; cmd ... || status=$?
	if test $status ...

which means the same thing but does not fail under "set -e".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: gitster

t/t9200-git-cvsexportcommit.sh

@@ -11,8 +11,8 @@ if ! test_have_prereq PERL; then
 	test_done
 fi
 
-cvs >/dev/null 2>&1
-if test $? -ne 1
+status=0; cvs >/dev/null 2>&1 || status=$?
+if test $status -ne 1
 then
     skip_all='skipping git cvsexportcommit tests, cvs not found'
     test_done