Disable Magma by default for Mad-Hatter builds
Disable Magma by default for Mad-Hatter builds

Magma isn't a supported storage engine for Mad-Hatter. Now we have a
mad-hatter branch for kv_engine, disable Magma by default so it's not
present in Mad-Hatter release builds.

Change-Id: I6993aad7d81c98ed2a177a3ba62c53feb327142f
Reviewed-on: http://review.couchbase.org/116969
Reviewed-by: Paolo Cocchi <9dd88c9f3e5cbab6e19a6c020f107e0c648ac956@couchbase.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine