the common references to lxc man pages
are now placed in one file "see_also.sgml.in"

Note that the few man pages that refer to man
pages that are not lxc ones have two "See Also" paragraph.
Signed-off-by: Michel Normand <normand@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>