For Bug 428063, need oldAppVersion for update verify when testing 3.0rc1 --> 3.0rc2

tools/release/configs/fx-moz19-staging-bootstrap.cfg

@@ -11,6 +11,7 @@ l10n_pullDate   = 2008-04-23 13:05 PDT
 build           = 1
 # oldVersion and oldRc refer to the previous release
 oldVersion      = 3.0rc1
+oldAppVersion   = 3.0
 oldBuild        = 2
 appName         = browser
 product         = firefox