Revert "fix tforwardgeneric"

This reverts commit d82a032566.

compiler/lambdalifting.nim

@@ -288,9 +288,6 @@ proc interestingVar(s: PSym): bool {.inline.} =
 proc semCaptureSym*(s, owner: PSym) =
   if interestingVar(s) and owner.id != s.owner.id and s.kind != skResult:
     if owner.typ != nil and not isGenericRoutine(owner):
-      # XXX: is this really safe?
-      # if we capture a var from another generic routine,
-      # it won't be consider captured.
       owner.typ.callConv = ccClosure
     #echo "semCaptureSym ", owner.name.s, owner.id, " ", s.name.s, s.id
     # since the analysis is not entirely correct, we don't set 'tfCapturesEnv'