Remove special completion handling for "fg" command.

The "fg" command only accepts one process name.  This special case
stops completing names after the first.  The "tail" command also
only accepts on name but the completion code doesn't have a case
for that.  These commands give an error if they get too many
arguments so special cases in the completion code aren't worth it.

supervisor/supervisorctl.py

@@ -275,9 +275,6 @@ class Controller(cmd.Cmd):
                        'status', 'tail'):
                 if not line.endswith(' ') and len(line.split()) == 1:
                     return [text + ' ', None][state]
-                if cmd == 'fg':
-                    if line.endswith(' ') and len(line.split()) > 1:
-                        return None
                 results = self.completionmatches(text,line)+[None]
                 return results[state]
             # commands that accept a group name