Add cmake file to detect availability of Google Breakpad

Change-Id: I32a3cdb75f3f06728530dce81eeff5e2f6f509d6
Reviewed-on: http://review.couchbase.org/43709
Tested-by: buildbot <build@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>
Reviewed-by: David Haikney <david.haikney@couchbase.com>