use proc_lib to spawn compaction daemon's compaction loop process
use proc_lib to spawn compaction daemon's compaction loop process

So that when this guy crashes SASL prints nice error report.

Change-Id: Ifd2b4ea5bb48f7481229ebda87e98fda18dfc4db
Reviewed-on: http://review.couchbase.org/13154
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>
Tested-by: Dale Harvey <491ccac09a36ad1e38b698f273b84fd8efc31071@arandomurl.com>
Reviewed-by: Dale Harvey <491ccac09a36ad1e38b698f273b84fd8efc31071@arandomurl.com>

nimishzynga/ns_server,membase/ns_server,vzasade/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,nimishzynga/ns_server,membase/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,daverigby/ns_server,nimishzynga/ns_server,ceejatec/ns_server,ceejatec/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,vzasade/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,ceejatec/ns_server,daverigby/ns_server,daverigby/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server,daverigby/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,vzasade/ns_server,membase/ns_server,mschoch/ns_server