One of the requirements for upgrading to Enterprise Manager Cloud Control 13c Release 2, is to apply.
Database patch set update 160419

While trying to apply the patch to Oracle GI + DB, it will error out with non existing files (more below…).

opatchauto apply 22899531

System initialization log file is /u01/app/grid/12.1.0.1/grid/cfgtoollogs/opatchautodb/systemconfig2016-10-06_02-29-43PM.log.

Session log file is /u01/app/grid/12.1.0.1/grid/cfgtoollogs/opatchauto/opatchauto2016-10-06_02-29-47PM.log
The id for this session is 136I
[init:init] Executing OPatchAutoBinaryAction action on home /u01/db/12.1.0.1/db_1

Executing OPatch prereq operations to verify patch applicability on SIDB Home........

[..] snip

Patch: 22899531/23006522
Log: /u01/app/grid/12.1.0.1/grid/cfgtoollogs/opatchauto/core/opatch/opatch2016-10-06_14-41-43PM_1.log
Reason: Failed during Patching: oracle.opatch.opatchsdk.OPatchException: 
Prerequisite check "CheckApplicable" failed. 

After fixing the cause of failure Run opatchauto resume with session id "136I"

]
OPATCHAUTO-68061: The orchestration engine failed.
OPATCHAUTO-68061: The orchestration engine failed with return code 1
OPATCHAUTO-68061: Check the log for more details.
OPatchAuto failed.

Note: ocm response file is not needed in latter versions.

A quick check in the log file shows the error below.

[Oct 6, 2016 2:54:06 PM]     Patch 23006522:
                             onewaycopyAction : Source File "/install/patch/db_patch/22899531/23006522/files/crs/install/dropdb.pl" does 
not exists or is not readable
                             'oracle.crs, 12.1.0.2.0': Cannot copy file from 'dropdb.pl' to '/u01/app/grid/12.1.0.1/grid/crs/install/drop
db.pl'
[Oct 6, 2016 2:54:06 PM]     Prerequisite check "CheckApplicable" failed.
                             The details are:

But the file do exists, and we are executing as root.
Note: Trying to run as the grid user will exit with an error.
“Cannot run as ‘grid’. Please run as root user.”

A simple solution to fix the issue (at least worked for me), was making all files world readable.

chmod -R +r 22899531

Then the install just completed without an issues

opatchauto resume
Session log file is /u01/app/grid/12.1.0.1/grid/cfgtoollogs/opatchauto/opatchauto2016-10-06_03-03-51PM.log
Resuming existing session with id 136I
[..] snip

==Following patches were SUCCESSFULLY applied:

Patch: 22899531/23006522
[..] snip