[Ada] Fix Codepeer warning

[Pierre-Marie de Rodat via Gcc-patches]

Codepeer was emitting a warning about Ifaces_List not being initialized.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * freeze.adb (Check_Inherited_Conditions): Initialize
        Ifaces_List.
diff --git a/gcc/ada/freeze.adb b/gcc/ada/freeze.adb
--- a/gcc/ada/freeze.adb
+++ b/gcc/ada/freeze.adb
@@ -1791,7 +1791,7 @@ package body Freeze is
          return Result;
       end Needs_Wrapper;
 
-      Ifaces_List    : Elist_Id;
+      Ifaces_List    : Elist_Id := No_Elist;
       Ifaces_Listed  : Boolean := False;
       --  Cache the list of interface operations inherited by R