test: replace shebangs with descriptions in shell libraries

A #! line in these files is misleading, since these scriptlets are
meant to be sourced with '.' (using whatever shell sources them)
instead of run directly using the interpreter named on the #! line.

Removing the #! line shouldn't hurt syntax highlighting since
these files have filenames ending with '.sh'.  For documentation,
add a brief description of how the files are meant to be used in
place of the shebang line.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/lib-httpd.sh

@@ -1,4 +1,31 @@
-#!/bin/sh
+# Shell library to run an HTTP server for use in tests.
+# Ends the test early if httpd tests should not be run,
+# for example because the user has not enabled them.
+#
+# Usage:
+#
+#	. ./test-lib.sh
+#	. "$TEST_DIRECTORY"/lib-httpd.sh
+#	start_httpd
+#
+#	test_expect_success '...' '
+#		...
+#	'
+#
+#	test_expect_success ...
+#
+#	stop_httpd
+#	test_done
+#
+# Can be configured using the following variables.
+#
+#    GIT_TEST_HTTPD              enable HTTPD tests
+#    LIB_HTTPD_PATH              web server path
+#    LIB_HTTPD_MODULE_PATH       web server modules path
+#    LIB_HTTPD_PORT              listening port
+#    LIB_HTTPD_DAV               enable DAV
+#    LIB_HTTPD_SVN               enable SVN
+#    LIB_HTTPD_SSL               enable SSL
 #
 # Copyright (c) 2008 Clemens Buchacher <drizzd@aon.at>
 #