Remove typestate_check reference to nonexistent ast.init node; rustc compiling...

Remove typestate_check reference to nonexistent ast.init node; rustc compiling itself notices what rustboot did not :)

src/comp/middle/typestate_check.rs

@@ -16,7 +16,6 @@
 import front.ast.ident;
 import front.ast.def_id;
 import front.ast.ann;
-import front.ast.init;
 import front.ast.expr;
 import front.ast.expr_call;
 import front.ast.expr_path;