t5551: use 'test_i18ngrep' to check translated output

The two tests 'invalid Content-Type rejected' and 'server-side error
detected' in 't5551-http-fetch-smart.sh' use "plain" 'grep' to check
that 'git clone' failed with the expected error message, but the
messages they are checking are translated, and, consequently, these
tests fail when the test script is run with GIT_TEST_GETTEXT_POISON
enabled.

Use 'test_i18ngrep' instead.

Signed-off-by: SZEDER Gábor <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: szeder

t/t5551-http-fetch-smart.sh

@@ -199,7 +199,7 @@ test_expect_success 'GIT_SMART_HTTP can disable smart http' '
 
 test_expect_success 'invalid Content-Type rejected' '
 	test_must_fail git clone $HTTPD_URL/broken_smart/repo.git 2>actual &&
-	grep "not valid:" actual
+	test_i18ngrep "not valid:" actual
 '
 
 test_expect_success 'create namespaced refs' '
@@ -466,7 +466,7 @@ test_expect_success 'GIT_TRACE_CURL_NO_DATA prevents data from being traced' '
 
 test_expect_success 'server-side error detected' '
 	test_must_fail git clone $HTTPD_URL/error_smart/repo.git 2>actual &&
-	grep "server-side error" actual
+	test_i18ngrep "server-side error" actual
 '
 
 test_done