Removing SpaceQuota from a namespace does not remove it completely

As demonstrated in HBASE-20662.master.002.patch setting quota on a namespace and removing it does not remove the quota setting from the tables in the namespace (which were added systematically due to namespace quota settings).

Steps:

• Create a namespace and a table in it
• Set space quota on namespace
• Violate namespace space quota
• Remove space quota on namespace
• Put row in table contained in namespace

public void setQuotaAndThenRemove(final String namespace, SpaceViolationPolicy policy)
    throws Exception {
  Put put = new Put(Bytes.toBytes("to_reject"));
  put.addColumn(Bytes.toBytes(SpaceQuotaHelperForTests.F1), Bytes.toBytes("to"),
    Bytes.toBytes("reject"));
  // Set quota and do puts until we violate space policy
  final TableName tn = writeUntilNSSpaceViolationAndVerifyViolation(namespace, policy, put);
  // Now, remove the quota
  removeQuotaFromNamespace(namespace);
  // Put some rows now: should not violate as quota settings removed
  verifyNoViolation(policy, tn, put);
}

Expected: We should be able to put data in contained table

Actual: We are not able to put data as SpaceQuota settings (systematically created due to previously added namespace space quota) exist on table