Contacts: Prevent NPE on multi select in local group select.

JIRA: CYAN-5788
https://jira.cyanogenmod.org/browse/CYAN-5788

Change-Id: I8d5daaf1b05372adcb19f10abc5533079f036e3f
Contacts: Don't reset cursor adapter in onPause.

  - Otherwise if user goes into multi-choice mode,
  selects multiple items, puts the device to sleep,
  and resumes -- they then don't see any items checkboxes
  marked correctly.

Change-Id: I0d9e1d8bee91892e392a12d55782dea018209fda