git-instaweb: support Fedora/Red Hat apache module path

On Fedora-derived systems, the apache httpd package installs modules
under /usr/lib{,64}/httpd/modules, depending on whether the system is
32- or 64-bit.  A symlink from /etc/httpd/modules is created which
points to the proper module path.  Use it to support apache on Fedora,
CentOS, and Red Hat systems.

Written with assistance of Todd Zullinger <tmz@pobox.com> and
Junio C Hamano <gitster@pobox.com>.

Signed-off-by: Sebastian Kisela <skisela@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-instaweb.sh b/git-instaweb.sh
index 47e38f3..675add1 100755
--- a/git-instaweb.sh
+++ b/git-instaweb.sh
@@ -326,13 +326,17 @@
 }
 
 apache2_conf () {
-	if test -z "$module_path"
-	then
-		test -d "/usr/lib/httpd/modules" &&
-			module_path="/usr/lib/httpd/modules"
-		test -d "/usr/lib/apache2/modules" &&
-			module_path="/usr/lib/apache2/modules"
-	fi
+	for candidate in \
+		/etc/httpd \
+		/usr/lib/apache2 \
+		/usr/lib/httpd ;
+	do
+		if test -d "$candidate/modules"
+		then
+			module_path="$candidate/modules"
+			break
+		fi
+	done
 	bind=
 	test x"$local" = xtrue && bind='127.0.0.1:'
 	echo 'text/css css' > "$fqgitdir/mime.types"