Only delete corrupt pickle config files if they exist

os.remove() raises OSError if the file being removed doesn't exist.
Check before calling to ensure we don't raise a useless exception
on an already deleted file.

Change-Id: I44c1c7dd97a47fcab8afb6c18fdf179158b6dab7
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed