in line 130 rlcompleter calls eval on the first part (before the last
dot) of the input text.
if that part is not valid it will raise an exception which is likely to
crash a calling application. 

example 1:
==========
import rlcompleter
rlcompleter.Completer().complete("foo.", 0) -> raises NameError

example 2:
==========
import rlcompleter
foo = 5
rlcompleter.Completer().complete("foo.bar.", 0) -> raises AttributeError

the patch puts the eval call in a try-except block and catches Name- and
AttributeErrors and returns an empty list (the behavior when no matches
are found).