Fix definition of LocalUseMapBuild so that it can build under stage0,

which does not have as many feature gates enabled.

src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs

@@ -97,7 +97,7 @@ impl LocalUseMap<'me> {
     }
 }
 
-struct LocalUseMapBuild<'me, 'map> {
+struct LocalUseMapBuild<'me, 'map: 'me> {
     local_use_map: &'me mut LocalUseMap<'map>,
     elements: &'me RegionValueElements,
 }