Check Settings > Safari to make sure the tab bar is enabled on your iPad. (It should not have been disabled during the upgrade, but it doesn't hurt to check the setting again.)
I'm guessing that you have a JavaScript bookmarklet in your tab bar that lets you view the source of the web page as that is not a feature of Safari for iOS.
If you have a Mac with Safari 6.1 (on 10.7 or 10.8) or Safari 7.0 on Mavericks (10.9), you can open Web Inspector from the Develop menu and connect to Safari for iOS on your iPad to view HTML source that way as well. You must have your iPad connected to your Mac via USB cable, and you have to go into Settings > Safari > Advanced and turn Web Inspector to ON.
To enable the Develop menu in Safari for Mac, open Safari preferences (Cmd-,), click on "Advanced" icon, then check the "Show Develop menu in menu bar" checkbox.
Hope that helps!