t3901: move supporting files into t/t3901/

The current convention is to either generate files on the fly in tests,
or to use supporting files taken from a t/tNNNN/ directory (where NNNN
matches the test's number, or the number of the test from which we
borrow supporting files).

The test t3901-i18n-patch.sh was obviously introduced before that
convention was in full swing, hence its supporting files still lived in
t/t3901-8859-1.txt and t/t3901-utf8.txt, respectively.

Let's adjust to the current convention.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t9500-gitweb-standalone-no-errors.sh b/t/t9500-gitweb-standalone-no-errors.sh
index 6d06ed9..cc8d463 100755
--- a/t/t9500-gitweb-standalone-no-errors.sh
+++ b/t/t9500-gitweb-standalone-no-errors.sh
@@ -519,7 +519,7 @@
 
 test_expect_success \
 	'encode(commit): utf8' \
-	'. "$TEST_DIRECTORY"/t3901-utf8.txt &&
+	'. "$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 &&
@@ -529,7 +529,7 @@
 
 test_expect_success \
 	'encode(commit): iso-8859-1' \
-	'. "$TEST_DIRECTORY"/t3901-8859-1.txt &&
+	'. "$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 &&