Changes

templates: fix osmo-msc.cfg.tmpl: add 'role asp', 'sctp-role client'

This commit fixes osmo-gsm-tester_virtual, which currently fails
because osmo-msc is unable to start:

DLSCCP NOTICE sccp_user.c:656 OsmoMSC-A-Iu: Requesting an SCCP
              simple client on ASP asp-clnt-OsmoMSC-A configured
              with 'sctp-role server'
DLSCCP ERROR sccp_user.c:661 OsmoMSC-A-Iu: Requesting an SCCP
             simple client on ASP asp-clnt-OsmoMSC-A configured
             with 'sctp-role server' but no matching xUA server
             was configured!

Change-Id: Ie29589b46c65707089ff2b22c3b139b7b435cc95