treewide: replace cache.h with more direct headers, where possible

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/url.c b/url.c
index bf318c0..2e1a9f6 100644
--- a/url.c
+++ b/url.c
@@ -1,5 +1,6 @@
-#include "cache.h"
+#include "git-compat-util.h"
 #include "hex.h"
+#include "strbuf.h"
 #include "url.h"
 
 int is_urlschemechar(int first_flag, int ch)