The value of vRtrMplsTpLsrRPInLabel specifies the reverse path (RP)
LSP ingress label used by the MPLS-TP LSR Path.
This object can be set only after vRtrMplsTpLsrRPEnabled is set to
'true'.
Once this object is set, the value may not be unset. To remove the
ingress label, one must set vRtrMplsTpLsrRPEnabled to 'false'.