[boost] [Format] [Patch] trivial fix to basic_format initialization order

basic_format's std::locale-taking constructors initialize the locale member variable out of order, causing distracting warnings on (at least) g++. Trivial patch against CVS head attached. -- Nathaniel -- "But in Middle-earth, the distinct accusative case disappeared from the speech of the Noldor (such things happen when you are busy fighting Orcs, Balrogs, and Dragons)."