avoid cursor leak in email provider

When cursor is done, the cursor must be closed to avoid cursor leak.

Merged by AOSP: https://android-review.googlesource.com/#/c/52910/

Change-Id: Iaaffed2c4e90dc4b17ae55fcedb242bf890b3dd5
Fix a Cursor leak

When cursor is done, the cursor must be closed to avoid cursor leak.

AOSP: https://android-review.googlesource.com/#/c/54993/

Change-Id: I8d837dd50473c3b14806f54ca8a78de14178b0cb
Initial commit.
Merge branch 'jb-mr1' of https://github.com/Root-Box/packages_apps_Email into jb-mr1