ignore netrwhist file
Merge pull request #271 from adjohnson916/master

Ignore .netrwhist" until rtp ordering is fixed

Because vundle modifies the directory that appears first in the rtp, some files that vim generates in the first directory in rtp end up in the vundle directory. This is a known issue in vundle but until it is resolved, ignore .netrwhhist when found in the vundle directory.