cpg.h, objdb.h, coroaph.h: more const/size_t

• include/corosync/cpg.h (cpg_callbacks_t):
• include/corosync/mar_cpg.h (marshall_to_mar_cpg_name_t):
• lib/cpg.c (cpg_join, cpg_leave):
• lib/cpg.c (cpg_mcast_joined): make iovec const.
• include/corosync/cpg.h (cpg_mcast_joined): update prototype

...

git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@2048 fd59a12c-fef9-0310-b244-a6a79926bd2f