Revert "[PECOFF][Driver] Remove quotes from command line arguments."

This reverts commit r187390 because we should not handle argv's quotes ourselves.

In Windows, unlike Unix, quotes are not processed by the shell. Instead the C
startup routine parses it as described in
http://msdn.microsoft.com/en-us/library/a1y7w461.aspx and pass the results to
main(). So, at the time when the control reaches main(), quotes that should be
removed has already been removed.

We still need to handle quotes in the response file and in .drectve section
ourselves. That will be addressed in different patches.

llvm-svn: 187534