Fix to quote column name in CassandraAdmin

Author: KodaiD

core/src/main/java/com/scalar/db/storage/cassandra/CassandraAdmin.java

@@ -421,7 +421,7 @@ public void dropColumnFromTable(String namespace, String table, String columnNam
     try {
       String alterTableQuery =
           SchemaBuilder.alterTable(quoteIfNecessary(namespace), quoteIfNecessary(table))
-              .dropColumn(columnName)
+              .dropColumn(quoteIfNecessary(columnName))
               .getQueryString();
 
       clusterManager.getSession().execute(alterTableQuery);