gitweb: Make i18n (encoding) tests in t9500 leave clean state

The most important issue is that after unsetting `i18n.commitencoding'
config variable t9500 no longer will use author and comitter name
containing ISO-8859-1 characters, which are invalid UTF-8 characters.

Besides it is good practice in general to clean up the state in tests.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9500-gitweb-standalone-no-errors.sh

@@ -446,6 +446,8 @@ test_expect_success \
 test_expect_success \
 	'encode(commit): utf8' \
 	'. "$TEST_DIRECTORY"/t3901-utf8.txt &&
+	 test_when_finished "GIT_AUTHOR_NAME=\"A U Thor\"" &&
+	 test_when_finished "GIT_COMMITTER_NAME=\"C O Mitter\"" &&
 	 echo "UTF-8" >> file &&
 	 git add file &&
 	 git commit -F "$TEST_DIRECTORY"/t3900/1-UTF-8.txt &&
@@ -454,11 +456,13 @@ test_expect_success \
 test_expect_success \
 	'encode(commit): iso-8859-1' \
 	'. "$TEST_DIRECTORY"/t3901-8859-1.txt &&
+	 test_when_finished "GIT_AUTHOR_NAME=\"A U Thor\"" &&
+	 test_when_finished "GIT_COMMITTER_NAME=\"C O Mitter\"" &&
 	 echo "ISO-8859-1" >> file &&
 	 git add file &&
 	 git config i18n.commitencoding ISO-8859-1 &&
+	 test_when_finished "git config --unset i18n.commitencoding" &&
 	 git commit -F "$TEST_DIRECTORY"/t3900/ISO8859-1.txt &&
-	 git config --unset i18n.commitencoding &&
 	 gitweb_run "p=.git;a=commit"'
 
 test_expect_success \