Is it really the WiFi not working thing or just that the symbol stays grey, i.e. no connection to google services = no push notifications?
I have the latter problem and was able to fix it using the help from this post: Help with Xprivacy settings relating to Google Apps
The part where you use a terminal emulator on the phone or adb from a PC and type
su
am startservice -n com.google.android.gsf/.gtalkservice.service.GTalkService