Fix leak

Added a missing delete

Bug: N/A
Test: ./runtests_asan.sh
Change-Id: I90682333faf2b12ae5cc8ad9fa35e406cf2332fc
diff --git a/aidl_language_y.yy b/aidl_language_y.yy
index 2cbbfa8..67a7b11 100644
--- a/aidl_language_y.yy
+++ b/aidl_language_y.yy
@@ -490,6 +490,7 @@
  : CONST type identifier '=' const_expr ';' {
     $2->SetComments($1->GetComments());
     $$ = new AidlConstantDeclaration(loc(@3), $2, $3->GetText(), $5);
+    delete $1;
     delete $3;
    }
  ;