Add OCF support

Add OCF support

Updated patch from Florian Haas from Linux-HA project.

User needs to 'configure --enable-ocf' to get file installed
by 'make install' target by default.
User can also use 'make install_ocf' to get only ocf files installed.
With disabled (default) ocf support - no ocf files are installed.

FIXME: ocf installation path needs to be kept in sync with pacemaker.
find better way and possible also better location.