pip freeze output has comments sometimes: ignore

The output of pip freeze can contain lines like

    ## FIXME: could not find svn URL in dependency_links for this
    package:

These shouldn't log an error about being unable to parse a comment.
Especially since the message pip is trying to deliver to the user will
generally be about the following line, which isn't displayed in salt
output.
Merge pull request #8076 from AccelerationNet/develop

pip freeze output has comments sometimes: ignore them