2 bugs when downloading wheels

[qwcode]

2 problems:

1. downloading directly from wheel paths or urls produces an exception due to the requirement not having a "name"

Exception:
Traceback (most recent call last):
  File "/home/qwcode/p/pip/pip/basecommand.py", line 129, in main
    status = self.run(options, args)
  File "/home/qwcode/p/pip/pip/commands/install.py", line 333, in run
    req.name for req in requirement_set.successfully_downloaded
TypeError: sequence item 0: expected string, NoneType found

2. the logic for downloading wheels is flawed in that dependencies of wheels won't be downloaded. the wheel dependency processing logic is in the wrong place.

[dholth]

I thought about editing run_egg_info() to just detect that it's in a wheel and perform a noop... since the info is already there.

[qwcode]

closing due to merge of #1527