Low: Correction of a problem calling typedef two times.

compile fails due to call double typedef.

gmake[2]: Entering directory `/root/cluster-packages/pacemaker/lib/common'
  CC     utils.lo
In file included from utils.c:54:
../../include/crm/common/mainloop.h:60: error: redefinition of typedef 'mainloop_io_t'
../../include/crm/common/ipcs.h:30: note: previous declaration of 'mainloop_io_t' was here
gmake[2]: *** [utils.lo] Error 1