autogeneration build cleanup

- add conf/.gitignore to be consistent with the rest of the git tree

- build conf/ before man/
  we don't express dir interdependencies, therefor sort the build order
  (this would require a full Makefile.am rework)

- conf/Makefile.am: ship all files required to build at runtime,
  and don't pre-ship what should be built
  fix clean target to remove all temporary files

- corosync.spec.in: add missing BuildRequires

- man/Makefile.am: move corosync.conf.5 to the correct target
  drop call to make -C conf/ (see above

Signed-off-by: Fabio M. Di Nitto <fdinitto@redhat.com>
man/Makefile.am: removing trailing whitespace

Signed-off-by: Jan Pokorný <jpokorny@redhat.com>