[Centos] some things missing from addons directory

[Joe Pruett]

i was using 'yum upgrade'.

the doxygen issue is that a new package must have been made, but the
addons directory didn't get updated.  it's not obvious what should be done
in that case.

the php-manual issue is just that php-manual isn't built anymore.  i was 
hoping that there was a way to tell yum (via the repositories) that a 
package was obsoleted by "nothing" and would just get removed.  i guess 
that a dummy package that has no new files but obsoletes all the old 
packages could do that.  kinda funky but might be helpful.