Revert "Revert "Move error_code.h into otautil.""

This reverts commit 26436d6d to re-land
"Move error_code.h into otautil.".

This way it stops requiring relative path ".." in LOCAL_C_INCLUDES
(uncrypt and edify). Soong doesn't accept non-local ".." in
"local_include_dirs".

This CL needs to land with device-specific module changes (e.g. adding
the dependency on libotautil).

Test: lunch aosp_{angler,bullhead,dragon,fugu,sailfish}-userdebug;
      mmma bootable/recovery
Change-Id: If193241801af2dae73eccd31ce57cd2b81c9fd96