Fix findbugs violations in test-provider and drop-test-karaf

Fix findbugs violations in test-provider and drop-test-karaf

- Field only ever set to null
- int value cast to float and then passed to Math.round
- Possible null pointer dereference in method on exception path
- Non-virtual method call passes null for non-null parameter
- Comparison of String parameter using == or !=
- Should be a static inner class
- Private method is never called
- int value cast to float and then passed to Math.round
- Unread field
- Unread field: should this field be static?
- Unused field
- Dead store to local variable
- Private method is never called
- Method uses the same code for two switch clauses
- Write to static field from instance method
- Field not initialized in constructor but dereferenced without null check

Change-Id: Ib09380d626ab9162c4308810fae9db90522269cf
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>