CBQE-0 increase timeout for rebalance to 900 seconds of swap_rebalance with compaction test cases

Change-Id: I3c67b794e88c0bc3b3a8a3291cf9a9aa7c70e4cc
Reviewed-on: http://review.couchbase.org/29629
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>