treewide: remove unnecessary cache.h includes in source files

We had several C files include cache.h unnecessarily.  Replace those
with an include of "git-compat-util.h" instead.  Much like the previous
commit, these have all been verified via both ensuring that
    gcc -E $SOURCE_FILE | grep '"cache.h"'
found no hits and that
    make DEVELOPER=1 ${OBJECT_FILE_FOR_SOURCE_FILE}
successfully compiles without warnings.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

serve.c

@@ -1,4 +1,4 @@
-#include "cache.h"
+#include "git-compat-util.h"
 #include "repository.h"
 #include "config.h"
 #include "pkt-line.h"
@@ -8,6 +8,7 @@
 #include "serve.h"
 #include "upload-pack.h"
 #include "bundle-uri.h"
+#include "trace2.h"
 
 static int advertise_sid = -1;
 static int client_hash_algo = GIT_HASH_SHA1;