Make misc:spawn_safe return the pid of the actual process
Make misc:spawn_safe return the pid of the actual process

It used to return the pid of the intermediary process, which isn't
very useful.

Change-Id: Ica690758409b06a747ed3fb5d69b9f449daab44e
Reviewed-on: http://review.northscale.com:8080/751
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

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