move state data from /var/spool to /var/lib

The spool is for queues, and keeping state information there is not quite
right.  See references for details.

Reference: http://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html#VARSPOOLAPPLICATIONSPOOLDATA
Reference: http://refspecs.linuxfoundation.org/FHS_2.3/fhs-2.3.html#VARLIBVARIABLESTATEINFORMATION
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
fix compiler warnings

Few of these.

f5gs.c:137:14: warning: passing 'const struct runtime_config *restrict'
to parameter of type 'struct runtime_config *' discards qualifiers

Signed-off-by: Sami Kerola <kerolasa@iki.fi>