fix: Exception doesn't catch NoSuchMethodError, Throwable does

I am getting NoSuchMethodError when using waitForFragmentByTag() on Gingerbread:

```
java.lang.NoSuchMethodError: android.app.Activity.getFragmentManager
at com.robotium.solo.Waiter.getFragment(Waiter.java:717)
at com.robotium.solo.Waiter.waitForFragment(Waiter.java:563)
at com.robotium.solo.Solo.waitForFragmentByTag(Solo.java:2401)
[...]
```

Partial reverse of https://github.com/RobotiumTech/robotium/commit/5398dc4e8e5b646f22f7f4aca700025dfefeb749. Exception is not a superclass of NoSuchMethodError, hence this error is not caught. Throwable is a superclass of NoSuchMethodError and catches everything.