convert: fix util.popen regression in darcs converter

hgext/convert/common.py

@@ -223,7 +223,7 b' class commandline(object):'
                 pass
         cmdline = [util.shellquote(arg) for arg in cmdline]
         cmdline += ['<', util.nulldev]
-        cmdline = util.quotecommand(' '.join(cmdline))
+        cmdline = ' '.join(cmdline)
         self.ui.debug(cmdline, '\n')
 
         self.prerun()