[5337] Altered boost lib test macro to handle static linking

[5337] Altered boost lib test macro to handle static linking

m4macros/ax_boost_for_kea.m4
    Altered the test to add "-static" flag and wrap the compilation
    in a call to libtool as we do in our Makefiles. This should make the
    test yield the same results as when we make.  This is important for
    -static as libtool may use .so if a .a is not available.  On systems
    which glibc .a's are not installed, our Makes with libtool would
    succeed where a call to just g++ will fail.