moved the etag.h to the right file

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-merge-1.4.x@677 152afb58-edef-0310-8abb-c4023f1b3aa9

src/http-header-glue.c

@@ -6,6 +6,7 @@
 #include "array.h"
 #include "buffer.h"
 #include "log.h"
+#include "etag.h"
 
 /*
  * This was 'borrowed' from tcpdump.

src/response.c

@@ -18,7 +18,6 @@
 #include "log.h"
 #include "stat_cache.h"
 #include "chunk.h"
-#include "etag.h"
 
 #include "connections.h"