Bug 840948 - Fix for missing nsis function 'ResetWin8PromptKeys' in builds that don't have enable-metro. Fixes Win64 build bustage. r=bbondy

browser/installer/windows/nsis/installer.nsi

@@ -283,7 +283,9 @@ Section "-Application" APP_IDX
   SetShellVarContext current  ; Set SHCTX to HKCU
   ${RegCleanMain} "Software\Mozilla"
   ${RegCleanUninstall}
+!ifdef MOZ_METRO
   ${ResetWin8PromptKeys}
+!endif
   ${UpdateProtocolHandlers}
 
   ClearErrors