Fixes collapsed rows in activity log and support views on iOS7.
Using UITableViewAutomaticDimension on the activity log and support views on iOS7 results in collapsed rows - so we need to test for iOS8 (or higher) before using it.  Also changed row height from 50 back to 44 to match the rest of the application.  Lastly, removed using automatic dimension from the settings view controller since it recently added heightForRowAtIndexPath (if/when we start doing DynamicText across the app, we may want to update the settings view controller to allow for automatic dimensions.)
Merge pull request #2697 from wordpress-mobile/issue/2694-support-view-mangled-ios7

Fix collapsed rows in activity log and support views on iOS7