Silence -Werror=implicit-fallthrough compiler errors - Patch from Monty.

The patch also fixes some potential bugs due to missing break
statements.

dbcon/joblist/jlf_subquery.cpp

@@ -85,8 +85,8 @@ void getColumnValue(ConstantColumn** cc, uint64_t i, const Row& row, const strin
                 *cc = new ConstantColumn(oss.str(), row.getIntField(i));
                 break;
             }
-
-        // else > 0; fall through
+            /* fall through */
+            /* else > 0 */
 
         case CalpontSystemCatalog::DECIMAL:
         case CalpontSystemCatalog::UDECIMAL:

dbcon/joblist/tupleaggregatestep.cpp

@@ -1307,7 +1307,7 @@ void TupleAggregateStep::prep1PhaseAggregate(
 
             case ROWAGG_AVG:
                 avgFuncMap.insert(make_pair(key, funct));
-
+                /* fall through */
             case ROWAGG_SUM:
             {
                 if (typeProj[colProj] == CalpontSystemCatalog::CHAR ||
@@ -1890,6 +1890,7 @@ void TupleAggregateStep::prep1PhaseDistinctAggregate(
                 else
                     break;
                 }
+                /* fall through */
 
                 case ROWAGG_COUNT_ASTERISK:
                 case ROWAGG_COUNT_COL_NAME:
@@ -3166,6 +3167,7 @@ void TupleAggregateStep::prep2PhasesAggregate(
                 // let fall through to add a count column for average function
                 if (aggOp != ROWAGG_AVG)
                     break;
+                /* fall through */
 
                 case ROWAGG_COUNT_ASTERISK:
                 case ROWAGG_COUNT_COL_NAME:
@@ -4048,6 +4050,7 @@ void TupleAggregateStep::prep2PhasesDistinctAggregate(
                     funct->fAuxColumnIndex = colAggPm;
                 else
                     break;
+                /* fall through */
 
                 case ROWAGG_COUNT_ASTERISK:
                 case ROWAGG_COUNT_COL_NAME:

dbcon/mysql/ha_mcs_execplan.cpp

@@ -3323,6 +3323,7 @@ ReturnedColumn* buildReturnedColumn(
                     break;
             }
         }
+        /* fall through */
 
         case Item::NULL_ITEM:
         {
@@ -4828,6 +4829,7 @@ ReturnedColumn* buildAggregateColumn(Item* item, gp_walk_info& gwi)
                             break;
                         }
                     }
+                    /* fall through */
 
                     default:
                     {

dbcon/mysql/ha_mcs_partition.cpp

@@ -263,6 +263,7 @@ const string format(int64_t v, CalpontSystemCatalog::ColType& ct)
 
         case CalpontSystemCatalog::TIME:
             oss << DataConvert::timeToString(v);
+            break;
 
         case CalpontSystemCatalog::CHAR:
         case CalpontSystemCatalog::VARCHAR: