applypatch: Remove the 'st' field from FileContents.

It used to keep track of the stat(2) info (e.g. st_mode/st_gid/st_uid)
while patching a file in file-based OTA.

Test: Build and use the new updater to apply an update on bullhead.
Change-Id: Ibf8f0f4b14298a9489bf24a2678bb279c5d9c8f3

applypatch/include/applypatch/applypatch.h

@@ -18,7 +18,6 @@
 #define _APPLYPATCH_H
 
 #include <stdint.h>
-#include <sys/stat.h>
 
 #include <functional>
 #include <memory>
@@ -33,7 +32,6 @@ struct Value;
 struct FileContents {
   uint8_t sha1[SHA_DIGEST_LENGTH];
   std::vector<unsigned char> data;
-  struct stat st;
 };
 
 // When there isn't enough room on the target filesystem to hold the patched version of the file,