Fix docstring for trace_integration (#130)

Author: werat

opencensus/trace/ext/requests/trace.py

@@ -28,7 +28,7 @@
 
 
 def trace_integration():
-    """Wrap the mysql connector to trace it."""
+    """Wrap the requests library to trace it."""
     log.info('Integrated module: {}'.format(MODULE_NAME))
 
     # Wrap the requests functions