Merging r155288:

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r155288 | d0k | 2012-04-21 09:05:27 -0700 (Sat, 21 Apr 2012) | 6 lines

Remove unused PointerLikeTypeTraits for IndexListEntry.

It set NumLowBitAvailable = 3 which may not be true on all platforms.  We only
ever use 2 bits (the default) so this assumption can be safely removed

Should fix PR12612.
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llvm-svn: 155375