Fix file name matching on remote host.

Fix file name matching on remote host.

I see the following fails in the remote host testing we do for mingw32
hosted GDB,

python print (symtab[1][0].symtab)^M
python.c^M
(gdb) FAIL: gdb.python/python.exp: Test decode_line current locationn filename

python print (symtab[1][0].symtab)^M
python.c^M
(gdb) FAIL: gdb.python/python.exp: Test decode_line python.c:26 filename

The test cases doesn't consider remote host and assumes that directory
on build also exists on host.  In this patch, we only match file base
name if host is remote, otherwise, match file with dir name.

gdb/testsuite:

2014-10-15  Yao Qi  <yao@codesourcery.com>

	* gdb.python/py-symbol.exp: Match file base name if host is
	remote, otherwise match file name with dir name.
	* gdb.python/py-symtab.exp: Likewise.
	* gdb.python/python.exp: Likewise.