[Boost-maint] [date_time] Fix locally defined but unused typedef warnings on GCC.

Subject: [Boost-maint] [date_time] Fix locally defined but unused typedef warnings on GCC.
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-03-01 15:45:49

Hi,

I'd like this pull request to be merged:

https://github.com/boostorg/date_time/pull/5

The commit is rather trivial, it removes unused typedefs to silence GCC 
warnings.