Noux: fix GDB arguments in run script

Noux generates 'argv[0]' for the initial child automatically (in contrast
to the 'config_args' library), so the first argument stated in the
configuration should not be the GDB program name.

Fixes #1062.

ports/run/noux_gdb.run

@@ -167,7 +167,6 @@ append config {
 				</fstab> }
 append config "
 				<start name=\"/bin/${tool_prefix}gdb\">
-					<arg value=\"/bin/${tool_prefix}gdb\"/>
 					<arg value=\"/gdb/${gdb_target_binary_name}\"/> "
 append config {
 					<arg value="-ex" /><arg value="set interactive-mode off" />