configure.ac: bump version to 5.1.27
configure.ac: bump version to 5.1.27

ardje/luaposix,zevv/luaposix,jimmyharris/luaposix,rrthomas/luaposix,rrthomas/luaposix,jimmyharris/luaposix,ardje/luaposix,snegovick/luaposix,snegovick/luaposix,luaposix/luaposix,zevv/luaposix