@Override
  protected boolean holdLock(MasterProcedureEnv env) {
    return true;
  }
Assign the regions on the crashed RS to other Rses.
<p/>
In this method we will go through all the RegionStateNodes of the give regions to find out
whether there is already an TRSP for the region, if so we interrupt it and let it retry on
other server, otherwise we will schedule a TRSP to bring the region online.
<p/>
We will also check whether the table for a region is enabled, if not, we will skip assigning
it.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/ServerCrashProcedure.java