test/rilmodem/sim: fix test-sim-removal

This changes fixes a fundemental flaw in the test-sim-removal
script.  The script used TestCase assert* methods in its callbacks
for timeout and DBus signals.  Any such asserts needs to be called
on the main unittest thread, or they're ignored by the framework.
 test/rilmodem/sim: add pin/puk unlock tests
Merge pull request #140 from tonyespy/sim-unlock-tests

Sim unlock tests