Fixes for make distcheck

make distcheck now finishes successfully for me *if* I have LIBMESH_DIR set. This is a separate issue that I will deal with later (basically --with-libmesh needs to be passed to DISTCHECK_CONFIGURE_FLAGS, but need to play with/decide on whether to go the boost.m4 route and put it directly in there or do AM_DISTCHECK_CONFIGURE_FLAGS in the Makefile.am)