Fix non iterable

[GustavoSchip]

Status

READY

Description

Fixes/prevents a 'TypeError: argument of type 'NoneType' is not iterable' error.
I defaulted to returning False when the initial return failed.

Original error

Traceback (most recent call last):
  File "C:\Users\***\source\routersploit\rsf.py", line 29, in <module>
    routersploit(sys.argv)
  File "C:\Users\***\source\routersploit\rsf.py", line 21, in routersploit
    rsf = RoutersploitInterpreter()
          ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\***\source\routersploit\routersploit\interpreter.py", line 214, in __init__
    super(RoutersploitInterpreter, self).__init__()
  File "C:\Users\***\source\routersploit\routersploit\interpreter.py", line 54, in __init__
    self.setup()
  File "C:\Users\***\source\routersploit\routersploit\interpreter.py", line 78, in setup
    if is_libedit():
       ^^^^^^^^^^^^
  File "C:\Users\***\source\routersploit\routersploit\interpreter.py", line 43, in is_libedit
    return "libedit" in readline.__doc__
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: argument of type 'NoneType' is not iterable

Verification

Provide steps to test or reproduce the PR.

1. Start ./rsf.py (On windows this was enough to trip the bug.)
2. Continue using the script (If you made it to this point the fix works.)

Checklist

• Write module/feature