coverage report: use --ignore-errors

We currently appear to collect coverage from pip-install, where then the
source is not available anymore.

Ref: #3923 (comment)

Author: blueyed

.travis.yml

@@ -97,7 +97,7 @@ after_success:
       pip install codecov
       coverage combine
       coverage xml
-      coverage report -m
+      coverage report -m --ignore-errors
       codecov --required -X gcov pycov search -f coverage.xml --flags ${TOXENV//-/ } linux
 
       # Coveralls does not support merged reports.

scripts/upload-coverage.bat

@@ -3,7 +3,7 @@ if not defined PYTEST_NO_COVERAGE (
     C:\Python36\Scripts\pip install codecov
     C:\Python36\Scripts\coverage combine
     C:\Python36\Scripts\coverage xml
-    C:\Python36\Scripts\coverage report -m
+    C:\Python36\Scripts\coverage report -m --ignore-errors
     C:\Python36\Scripts\codecov --required -X gcov pycov search -f coverage.xml --flags %TOXENV:-= % windows
 ) else (
     echo Skipping coverage upload, PYTEST_NO_COVERAGE is set