package.bbclass: Make package output files more deterministic

package.bbclass: Make package output files more deterministic

Observing depsig.do_package for packages inbetween rebuilds indicated
that the following variables/files content was changing order randomly.
Make them deterministic by sorting the output:

 RDEPENDS_<pkg>
 RRECOMMENDS_<pkg>
 FILERDEPENDSFLIST_<pkg>

 packages-split/<pkg>.shlibdeps

The following variable was not observed to change, but it is
assumed that the same situation can occur, so do the same
sorting for consistency:

 FILERPROVIDESFLIST_<pkg>

Signed-off-by: Jacob Kroon <jacob.kroon@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>