Fix precedence error in retrieve_offsets

As noted by @ClemensLinnhoff there is a precedence error in
retrieve_offsets of osi3trace which results in errors if the function is
called again after a complete read.

Signed-off-by: Pierre R. Mai <pmai@pmsf.de>

osi3trace/osi_trace.py

@@ -54,8 +54,8 @@ def retrieve_offsets(self, limit=None):
         if not self.read_complete:
             self.current_index = len(self.message_offsets) - 1
             self.file.seek(self.message_offsets[-1], 0)
-        while (
-            not self.read_complete and not limit or len(self.message_offsets) <= limit
+        while not self.read_complete and (
+            not limit or len(self.message_offsets) <= limit
         ):
             self.retrieve_message(skip=True)
         return self.message_offsets