Return argument to do_man back

Revert a part of b3c5204, the do_main has to have at least one
argument, unless following exception will appear

osc.cmdln.CmdlnError: incorrect argcount for do_man(): takes 1, must
take 2 for 'argv' signature or 3+ for 'opts' signature

Signed-off-by: Petr Uzel <puzel@suse.cz>
Signed-off-by: Michal Vyskocil <mvyskocil@suse.cz>

osc/cmdln.py

@@ -559,7 +559,7 @@ class RawCmdln(cmd.Cmd):
     do_help.aliases = ["?"]
 
 
-    def do_man(self):
+    def do_man(self, argv):
         """${cmd_name}: generates a man page
 
         usage: