WebHomePath was always "/SelfService" when WebPath was defined

Concatenation is higher precedence than the ternary operator, leading
the WebHomePath to effectively be:

    (WebPath . !Privileged) ? "/SelfService" : ""

...which was a correct formulation as long as WebPath was empty, but
which forced WebHomePath to "/SelfService" whenever WebPath was set,
breaking autocompletion.

Add parentheses to fix the precedence.
Merge branch '4.2/webhomepath-with-webpath'