virt-xml: add "-c" as short option of "--connect"

Add "-c" as short option of "--connect" for virt-xml.

We could use either
virt-xml -c lxc:///
or
virt-xml --connect lxc:///

This will be more convenient if we operate
non-default hypervisor.

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>

man/virt-xml.pod

@@ -37,7 +37,7 @@ Show the help message and exit
 
 Show program's version number and exit
 
-=item  --connect=URI
+=item  -c URI, --connect=URI
 
 Connect to a non-default hypervisor. See L<virt-install(1)> for details
 

virt-xml

@@ -299,7 +299,7 @@ def parse_args():
         _("Edit libvirt XML using command line options."),
         introspection_epilog=True)
 
-    cli.add_connect_option(parser)
+    cli.add_connect_option(parser, "virt-xml")
 
     parser.add_argument("domain", nargs='?',
         help=_("Domain name, id, or uuid"))

virtinst/cli.py

@@ -552,9 +552,13 @@ def set_os_variant(obj, distro_type, distro_variant):
 # Common CLI option/group   #
 #############################
 
-def add_connect_option(parser):
-    parser.add_argument("--connect", metavar="URI",
-                      help=_("Connect to hypervisor with libvirt URI"))
+def add_connect_option(parser, invoker=None):
+    if invoker == "virt-xml":
+        parser.add_argument("-c", "--connect", metavar="URI",
+                help=_("Connect to hypervisor with libvirt URI"))
+    else:
+        parser.add_argument("--connect", metavar="URI",
+                help=_("Connect to hypervisor with libvirt URI"))
 
 
 def add_misc_options(grp, prompt=False, replace=False,