(*,G) mroute uptime is not updated in mroute table, after deleting and adding the RP

[vijaykug]

Did you check if this is a duplicate issue? [X] Did you test it on the latest FRRouting/frr master branch? [X]

Related Issue: [NA]

Description

(*,G) mroute uptime is not updated , after deleting and adding the RP

Steps to Reproduce

Setup :- Receiver-------R1-----R2(RP) (225.1.1.1)

1) IGMP group is received on R1 below is output for "show ip igmp groups" and "show ip mroute" note the uptime for both

Interface Address         Group           Mode Timer    Srcs V Uptime  
ens256    45.1.1.1        225.1.1.1       ---- 00:03:01    1 2 00:04:11 <<<```

```R1_6_2(config)# do show ip mroute 
Source          Group           Proto  Input      Output     TTL  Uptime
*               225.1.1.1       IGMP   ens192     pimreg     1    00:03:59
                                IGMP              ens256     1    00:03:59 <<<```

2) Remove the RP config,  ( *, G ) entry got removed from mroute table which is expected 

```R1_6_2(config)# do show ip igmp groups 
Interface Address         Group           Mode Timer    Srcs V Uptime  
ens256    45.1.1.1        225.1.1.1       ---- 00:02:59    1 2 00:04:13```

```R1_6_2(config)# do show ip mroute 
Source          Group           Proto  Input      Output     TTL  Uptime ```

3) Reconfigure the RP , observing mroute uptime is old (same as IGMP uptime)
  Here my expectation is mroute uptime should get cleared and start again

```R1_6_2(config)# do show ip igmp groups 
Interface Address         Group           Mode Timer    Srcs V Uptime  
ens256    45.1.1.1        225.1.1.1       ---- 00:02:43    1 2 00:04:29```

```R1_6_2(config)# do show ip mroute 
Source          Group           Proto  Input      Output     TTL  Uptime
*               225.1.1.1       IGMP   ens192     pimreg     1    00:04:37  
                                IGMP              ens256     1    00:04:37 <<< ```

**Expected behavior:**
 mroute uptime should get cleared and start again

**Actual behavior:**
  mroute uptime is showing as IGMP uptime

### Components
[pimd]

### Versions
* OS: [name] [version] - 16.04.1
* Kernel: [Linux/BSD] [version] - 4.18
* FRR: [version]                          - 6.02

Thanks!

[patrasar]

We will take this issue.

[ton31337]

@patrasar is this fixed?