minor fixes

Signed-off-by: Varsha GS <varsha.gs@ibm.com>

Author: GSVarsha

instana/instrumentation/boto3_inst.py

@@ -17,7 +17,7 @@
     from boto3.s3 import inject
 
     def extract_custom_headers(span, headers):
-        if agent.options.extra_http_headers is None:
+        if agent.options.extra_http_headers is None or headers is None:
             return
         try:
             for custom_header in agent.options.extra_http_headers:

tests/clients/boto3/test_boto3_lambda.py

@@ -10,8 +10,6 @@
 from sys import version_info
 if version_info >= (3, 8):
   from moto import mock_aws
-else:
-  from moto import mock_lambda as mock_aws
 
 from instana.singletons import tracer, agent
 from ...helpers import get_first_span_by_filter