vstart.sh: run multiple rgws with different ids

vstart.sh: run multiple rgws with different ids

We should expect being able to run multiple rgws with different ids
using vstart, and yet that was not the case as they were sharing the
same name (and same key).

We now mimic each rgw running on a different host, with ids being their
ports; as such, we'll have 'client.rgw.X', 'client.rgw.X+1', and so
forth. These will match the ports the daemons are running on.

Signed-off-by: Joao Eduardo Luis <joao@suse.com>