lnrpc: update golang proto compiler
lnrpc: update golang proto compiler

The newest version has changed the generated gRPC source files a bit.
If you’re running the _newset_ version of gRPC against the previously
generated code, you’ll get a compile error.

This commit fixes the above behavior.

aakselrod/lnd,BitfuryLightning/lnd,BitfuryLightning/lnd,ddustin/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,LightningNetwork/lnd,bryanvu/lnd,LightningNetwork/lnd,AndrewSamokhvalov/lnd,aakselrod/lnd,bryanvu/lnd