Do not load keyspace when creating sstable writer

patch by carlyeks; reviewed by yukim for CASSANDRA-10443

CHANGES.txt

@@ -1,4 +1,5 @@
 3.0
+ * Do not load keyspace when creating sstable writer (CASSANDRA-10443)
  * If node is not yet gossiping write all MV updates to batchlog only (CASSANDRA-10413)
  * Re-populate token metadata after commit log recovery (CASSANDRA-10293)
  * Provide additional metrics for materialized views (CASSANDRA-10323)

src/java/org/apache/cassandra/io/sstable/SSTableTxnWriter.java

@@ -104,12 +104,6 @@ public class SSTableTxnWriter extends Transactional.AbstractTransactional implem
     @SuppressWarnings("resource") // log and writer closed during postCleanup
     public static SSTableTxnWriter create(CFMetaData cfm, Descriptor descriptor, long keyCount, long repairedAt, int sstableLevel, SerializationHeader header)
     {
-        if (Keyspace.open(cfm.ksName).hasColumnFamilyStore(cfm.cfId))
-        {
-            ColumnFamilyStore cfs = Keyspace.open(cfm.ksName).getColumnFamilyStore(cfm.cfId);
-            return create(cfs, descriptor, keyCount, repairedAt, sstableLevel, header);
-        }
-
         // if the column family store does not exist, we create a new default SSTableMultiWriter to use:
         LifecycleTransaction txn = LifecycleTransaction.offline(OperationType.WRITE, descriptor.directory);
         MetadataCollector collector = new MetadataCollector(cfm.comparator).sstableLevel(sstableLevel);

test/unit/org/apache/cassandra/io/sstable/CQLSSTableWriterClientTest.java

@@ -45,7 +45,7 @@ public class CQLSSTableWriterClientTest
     public void setUp()
     {
         this.testDirectory = Files.createTempDir();
-        Keyspace.setInitialized();
+        Config.setClientMode(true);
     }
 
     @After