kill various DepNode variants

Author: nikomatsakis

src/librustc/dep_graph/dep_node.rs

@@ -315,12 +315,10 @@ define_dep_nodes!(
     Coherence,
     Resolve,
     CoherenceCheckTrait(DefId),
-    Variance,
     PrivacyAccessLevels(CrateNum),
 
     // Represents the MIR for a fn; also used as the task node for
     // things read/modify that MIR.
-    MirKrate,
     Mir(DefId),
     MirShim(DefIdList),
 
@@ -350,7 +348,6 @@ define_dep_nodes!(
     InherentImpls(DefId),
     TypeckBodiesKrate,
     TypeckTables(DefId),
-    UsedTraitImports(DefId),
     ConstEval(DefId),
     SymbolName(DefId),
     SpecializationGraph(DefId),