The value of vRtrMplsS2lSubLspIsFastRetry indicates which retry
timer is being referred to by vRtrMplsS2lSubLspRetryTimeRemain.
When the value of vRtrMplsLspPathIsFastRetry is set to 'true',
vRtrMplsLspPathRetryTimeRemaining is referring to the P2MP
S2L path fast timer, vRtrMplsGenP2mpS2lFastRetry.
When the value of vRtrMplsLspPathIsFastRetry is set to 'false',
vRtrMplsS2lSubLspRetryTimeRemain is referring to the LSP retry timer,
vRtrMplsLspRetryTimer.