totemconfig: Key change process dependencies

totemconfig: Key change process dependencies

When key with dependency was changed, dependant keys were not recomputed.
Nice example is consensus timeout. If token timout was changed,
consensus timeout was not recomputed correctly (nether via cmap change
of key nor via cfg reload).

Solution is almost complete refactor of handling volatile defaults.

totem_volatile_config_read now handles not only storing cmap key to
totem_config structure, but also checking of existence, comparing with
zero value and properly storing defaults.

totem_set_volatile_defaults is gone. It's function was splitted into
totem_volatile_config_read and totem_volatile_config_validate functions.

Reload callback and change of key callback are now mostly same functions
and both calls totem_volatile_config_read.

Patch also fixes small memory leak. totem.vsftype key is not used for
long time and original totem_volatile_config_read wasn't freeing
allocated memory returned by icmap_get_string. Whole reading of
totem.vsftype is removed.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>