Moved mon.c to the first host with mon.a and mon.b to address the issue

Sage found:
"... supposed to have half dumpling, half x osds. but the steps that upgrade and restart the mons upgrade the packages on the second host (which should remain dumpling w/ osd 3,4,5)"

Signed-off-by: Yuri Weinstein <yuri.weinstein@inktank.com>