t: prepare test_match_signal () calls for set -e

We have a couple of calls to `test_match_signal ()` where we execute a
Git command and expect it to die with a specific signal. These calls
will essentially execute the process in a subshell via `foo; echo $?`,
but as we expect `foo` to fail this will cause the overall subshell to
fail once we `set -e`.

Fix this issue by using `foo && echo 0 || echo $?` instead.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

t/t0005-signals.sh

@@ -42,12 +42,12 @@ test_expect_success 'create blob' '
 '
 
 test_expect_success !MINGW 'a constipated git dies with SIGPIPE' '
-	OUT=$( ((large_git; echo $? 1>&3) | :) 3>&1 ) &&
+	OUT=$( ((large_git && echo 0 1>&3 || echo $? 1>&3) | :) 3>&1 ) &&
 	test_match_signal 13 "$OUT"
 '
 
 test_expect_success !MINGW 'a constipated git dies with SIGPIPE even if parent ignores it' '
-	OUT=$( ((trap "" PIPE && large_git; echo $? 1>&3) | :) 3>&1 ) &&
+	OUT=$( ((trap "" PIPE && large_git && echo 0 1>&3 || echo $? 1>&3) | :) 3>&1 ) &&
 	test_match_signal 13 "$OUT"
 '
 

t/t3600-rm.sh

@@ -260,7 +260,7 @@ test_expect_success 'choking "git rm" should not let it die with cruft (induce S
 
 test_expect_success !MINGW 'choking "git rm" should not let it die with cruft (induce and check SIGPIPE)' '
 	choke_git_rm_setup &&
-	OUT=$( ((trap "" PIPE && git rm -n "some-file-*"; echo $? 1>&3) | :) 3>&1 ) &&
+	OUT=$( ((trap "" PIPE && git rm -n "some-file-*" && echo 0 1>&3 || echo $? 1>&3) | :) 3>&1 ) &&
 	test_match_signal 13 "$OUT" &&
 	test_path_is_missing .git/index.lock
 '