build: Make distcheck work for non-root user

make distcheck calls configure script with --prefix to allow
installation to tmp directory. ocfdir is not using ${prefix} and instead
contains absolute path (either taken from resource-agents.pc or
hardcoded one) so make install fails when running as non-root user.

Solution is taken from pacemaker project and it relies on setting
AM_DISTCHECK_CONFIGURE_FLAGS so --with-ocfdir is added with directory
where user has write permissions.

Big thanks to Fabio M. Di Nitto <fdinitto@redhat.com> for finding this
solution.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>