Let edit-node install multiple packages

Previously, the manpage specified one syntax for installing
multiple packages, but edit-node did not parse it correctly. Make
the behaviour match the manpage.

Change-Id: Ic6973a43641a8f540d2237d4a5afcf27d8741a97
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=991289
Signed-off-by: Ryan Barry <rbarry@redhat.com>