Update to libcouchbase 2.3.1.

Change-Id: I539aaa8978c965c79c0ed578ac446ecd86596712
Release 1.2.3

Change-Id: I85d4f6106a22316144ecf6d6a093ea8219c5daf0
Correct build error from libcouchbase 2.3.1 update.

Change-Id: Icd707fbbc9b7cba50172699cb3be9e2b1c6f11f3
Release 1.2.4

1.2.3 had build errors and was never released.

Change-Id: I307027f87b379f5f9d51add13f94f29563d88120
WIP: CAVES integration.

Change-Id: Ib35ba24a36d10815c7d92e3cf0103dc9eaf9a47c