Add some sanity checking for GATT responses.
Add some sanity checking for GATT responses.

X-Original-Commit: 54453e47624d7ba15980063909c5effe87f21b6d

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble