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>

imap-send.c

@@ -21,7 +21,7 @@
  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "cache.h"
+#include "git-compat-util.h"
 #include "config.h"
 #include "credential.h"
 #include "exec-cmd.h"