[PATCH] Add support to print version.

[Shankar Kalpathi Easwaran]

I have changed the commit message but for some reason, its not appearing as part of the new diff. You will see it when I commit.

This is how it looks just FYI.


    Add support to print version.

    Summary: This adds support in the UniversalDriver to print the linker version and the
    repository version.

    Test Plan: A driver test is added

    Differential Revision: http://reviews.llvm.org/D5641

http://reviews.llvm.org/D5641