Coverity issues in contrail-controller/cfg_mirror.cc

I have run Coverity on branch R5.0 and it reported the following issues
in contrail-controller/cfg_mirror.cc:
- Variable entry going out of scope leaks the storage it points to in
cfg_mirror.cc:MirrorCfgTable::Add
- Variable entry going out of scope leaks the storage it points to in
cfg_mirror.cc:IntfMirrorCfgTable::Add

Indeed, in both functions listed above, variable entry is not freed on
else branch.

Change-Id: Ia083a3976bd1259e415195ae916a8dd377d50ffc
Closes-Bug: #1770158
Signed-off-by: Anda Nicolae <anicolae@lenovo.com>

src/vnsw/agent/cfg/cfg_mirror.cc

@@ -138,6 +138,7 @@ const char *MirrorCfgTable::Add(const MirrorCreateReq &cfg) {
                                     cfg.get_vni(), mirror_flag,
                                     MacAddress::ZeroMac());
     } else {
+        delete entry;
         return "Mode not supported";
     }
 
@@ -512,6 +513,7 @@ const char *IntfMirrorCfgTable::Add(const IntfMirrorCreateReq &intf_mirror) {
                                      intf_mirror.get_vni(), mirror_flag,
                                      MacAddress::ZeroMac());
      } else {
+        delete entry;
         return "not supported";
      }
 intf_update: