webcommands: stop using ersatz if-else ternary operator for rename variable 6ddc86eedc3b didn't remove it, let's do it now. Placing the added lines into the already existing "if fctx is not None" block also makes webcommands.comparison() look a bit more like webcommands.filediff(), which eases possible future refactoring. And fctx is not None only when path in ctx, so logically it's equivalent.