CRM-14399 add alterCalculatedMembershipStatus hook

merge for 4.4.10 once 4.4.9 is out as 4.4.9 in pre-release mode

Note this has been running & the hook has been used on fuzion sites for several months now & I'm of the opinion that getting it into core 4.4. in addition to providing developer consistency is also less risky than porting further patches without syncing this up