A question about Master failover

[Gaojinchao]

In function rebuildUserRegions,  The region that regionLocation is null is put 
into regions set. It seems a bug.
It will throw exception when DisableTableHandler processes it.  Skipping this 
region seems better.

code:
if (regionLocation == null) {
        // Region not being served, add to region map with no assignment
        // If this needs to be assigned out, it will also be in ZK as RIT
        // add if the table is not in disabled state
        if (false == checkIfRegionBelongsToDisabled(regionInfo)) {
          this.regions.put(regionInfo, null);
        }
        if (checkIfRegionBelongsToDisabling(regionInfo)) {                 
//Should we skip this region?
          disablingTables.add(disablingTableName);
        }
} else if (!serverManager.isServerOnline(regionLocation.getServerName())) {