Bug#1017730: pmix: drop Build-Depends: pandoc

[Drew Parsons]

Incidentally the man pages don't seem to be getting installed.  I'm not 
sure how it should be done via make install (they get listed in 
EXTRA_DIST).  Possibly easier to just create a 
debian/libpmix-bin.manpages and let dh_installman install them directly 
from source.

Drew