Merge libmounts into libotautil.

Export its header (mounts.h) from there, and drop the dot dot dependency
from libupdater / updater.

Test: mmma bootable/recovery
Test: recovery_component_test
Change-Id: Ic26a6b9b78a34dbe1f178b138f3abaafffbec44c
diff --git a/updater/install.cpp b/updater/install.cpp
index 6732ab8..5623c33 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -57,10 +57,10 @@
 #include <ziparchive/zip_archive.h>
 
 #include "edify/expr.h"
-#include "mounts.h"
 #include "otafault/ota_io.h"
 #include "otautil/DirUtil.h"
 #include "otautil/error_code.h"
+#include "otautil/mounts.h"
 #include "otautil/print_sha1.h"
 #include "updater/updater.h"