fix up gdb.mi

fix up gdb.mi

This fixes gdb.mi to be parallel-safe.

2013-11-04  Tom Tromey  <tromey@redhat.com>

	* gdb.mi/mi-cmd-param-changed.exp (test_command_param_changed):
	Use "dwarf2 always-disassemble" for the "maint set" test.
	* gdb.mi/mi-file-transfer.exp (test_file_transfer): Use
	standard_output_file.
	* gdb.mi/mi-logging.exp: Use standard_output_file.