Typo in fetching gtk-bookmarks causes exception

[avihayb]

https://github.com/j4321/tkFileBrowser/blob/master/tkfilebrowser/filebrowser.py#L382
path_bm = join(home, ".config", "gtk-3.0", "bookmarks")
path_bm2 = join(home, ".gtk-bookmarks") # old location
if exists(path_bm):
with open(path_bm) as f:
bms = f.read().splitlines()
elif exists(path_bm2):
with open(path_bm) as f:
*** ^ ***
bms = f.read().splitlines()
else:

path_bm should be path_bm2 or the dialog crashes with file not found