Cut disabling uninitialized warnings in folly/experimental/Bits.h (#1033)
Cut disabling uninitialized warnings in folly/experimental/Bits.h (#1033)

Summary:
- `folly/experimental/Bits.h` has a section where we disable two
  uninitialized-flavors of warnings that were needed for GCC 4.8
- Since we do not support GCC 4.8 anymore and GCC 5.1 does not have
  issues with this, do not disable the warnings anymore.
Pull Request resolved: https://github.com/facebook/folly/pull/1033

Reviewed By: Orvid

Differential Revision: D14223285

Pulled By: yfeldblum

fbshipit-source-id: 0088341b13e26dff2dc90a768319cccc45e942da

facebook/folly,facebook/folly,facebook/folly,facebook/folly,facebook/folly