Changes in the current SRU cycle schedule

[Kleber Souza]

IMPORTANT NOTE: due to the release of 18.04.2 being delayed until
February 14th, we are extending the current kernel SRU cycle by a
week.

So the new schedule for the current and next cycles is:

cycle: 04-Feb through 03-Mar
====================================================================
         30-Jan   Last day for kernel commits for this cycle.
04-Feb - 15-Feb   Kernel prep week(s).
18-Feb - 01-Mar   Bug verification & Regression testing.
         04-Mar   Release to -updates.


cycle: 04-Mar through 24-Mar
====================================================================
         27-Feb Last day for kernel commits for this cycle.
04-Mar - 08-Mar Kernel prep week.
11-Mar - 22-Mar Bug verification & Regression testing.
         25-Mar Release to -updates.