fix some fission tests

fix some fission tests

A couple of Fission tests rely on the current directory layout.  This
assumption is not valid in parallel mode.

This patch fixes the problem by removing the relative directory from
the .S files and instead having the tests set debug-file-directory
before opening the main file.

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

	* gdb.dwarf2/fission-base.S: Remove "gdb.dwarf/".
	* gdb.dwarf2/fission-base.exp: Set debug-file-directory
	before loading binfile.
	* gdb.dwarf2/fission-loclists.S: Remove "gdb.dwarf/".
	* gdb.dwarf2/fission-loclists.exp: Set debug-file-directory
	before loading binfile.