test-lib: Clean up comments and Makefile.

Bring documentation in test-lib and clean target
in Makefile in-line with abc5d372.

Signed-off-by: Emil Sit <sit@emilsit.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/Makefile

@@ -24,7 +24,7 @@ pre-clean:
 	$(RM) -r test-results
 
 clean:
-	$(RM) -r 'trash directory' test-results
+	$(RM) -r 'trash directory'.* test-results
 
 aggregate-results-and-cleanup: $(T)
 	$(MAKE) aggregate-results

t/test-lib.sh

@@ -441,14 +441,6 @@ test_done () {
 	fi
 	case "$test_failure" in
 	0)
-		# We could:
-		# cd .. && rm -fr 'trash directory'
-		# but that means we forbid any tests that use their own
-		# subdirectory from calling test_done without coming back
-		# to where they started from.
-		# The Makefile provided will clean this test area so
-		# we will leave things as they are.
-
 		say_color pass "passed all $msg"
 
 		test -d "$remove_trash" &&