CBLT-319:  parameters are now positional:

usage:  mobile-staging.sh  RELEASE  VERSION  PRODUCT  EDITION  [ -D TMP_DIR ]

           RELEASE        release number, like 3.0.0 or 2.5.2
           VERSION        prepared version, like 3.0.0 or 3.0.0-beta
           PRODUCT        android, ios, or sync_gateway (one only)
           EDITION        community or enterprise.

          [-D TMP_DIR ]   temp dir to use, if not /Users/plabee/release_tmp

           -h             print this help message

Change-Id: I938d60d282321c2cd4609b0355ebbf5e20be93c6
Reviewed-on: http://review.couchbase.org/38522
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>