Log: all: overhaul log locations

Add new configure options for the directories of the main pacemaker log and
pacemaker bundle logs. The new defaults for these locations are
/var/log/pacemaker and /var/log/pacemaker/bundles, respectively.

An example of how to configure them to use /var/log/cluster instead:

./configure --with-logdir=/var/log/cluster --with-bundledir=/var/log/cluster/bundles

Some trivial changes to log handling are included, such as the fencing
regression test now using corosync.test.log as its log name.