Retry Db_AddColumnSync failure in CreateTables

It is observed that sometimes the cassandra connection/session returns
no host available error on startup after adding few tables when trying
to update the SystemObjectTable in CreateTables. We need to retry in
this scenario instead of asserting.

Change-Id: I09f16367c40101faced382042d8a301c6764a921
Closes-Bug: #1529563

src/analytics/db_handler.cc

@@ -232,7 +232,9 @@ bool DbHandler::CreateTables() {
         columns.push_back(stat_col);
 
         if (!dbif_->Db_AddColumnSync(col_list)) {
-            VIZD_ASSERT(0);
+            DB_LOG(ERROR, g_viz_constants.SYSTEM_OBJECT_TABLE <<
+                ": Start Time Column Add FAILED");
+            return false;
         }
     }
 
@@ -267,7 +269,9 @@ bool DbHandler::CreateTables() {
         columns.push_back(stat_col);
 
         if (!dbif_->Db_AddColumnSync(col_list)) {
-            VIZD_ASSERT(0);
+            DB_LOG(ERROR, g_viz_constants.SYSTEM_OBJECT_TABLE <<
+                ": TTL Column Add FAILED");
+            return false;
         }
     }