Proper loading of trezor_pb2.py

bitkeylib/__init__.py

@@ -1,6 +1,6 @@
 try:
-    import bitkey_pb2 as proto
+    import trezor_pb2 as proto
 except ImportError:
-    print "bitkey_pb2.py not found. Please run /protobuf/build.sh to generate it!"
+    print "trezor_pb2.py not found. Please run /protobuf/build.sh to generate it!"
     import sys
     sys.exit()