ECalComponent: Recurrence ID not rescan properly

The e_cal_component_rescan() didn't update the recur_id private member
when the modified component didn't have it, it was left with the old
property instance set, which resulted in an incorrect return value
from the e_cal_component_is_instance().
Limit SQLite busy-wait for a lock

The previous busy-wait could cause flood of the kernel with a lock
request, with basically no outer limit. This change adds a 15 seconds
time limit with a 100 ms delay between each lock request.
Bug 736947 - Attachment icon not shown in Sent folder