llvm/CodeGen/CommandFlags.h: Prune doubleslash in #include.
llvm/CodeGen/CommandFlags.h: Prune doubleslash in #include.

While packaging 3.7 for Fedora, the debug info splitting
process fell over this, so fix it upstream seems like a good plan.

This should be put in the 3.7 branch as well.

Noticed by Dave Airlie <airlied@redhat.com>

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@247757 91177308-0d34-0410-b5e6-96231b3b80d8

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