[coverage] dont complain if tests dont hit defensive assertion code

.coveragerc

@@ -9,7 +9,7 @@ omit = ./GPy/testing/*.py, travis_tests.py, setup.py, ./GPy/__version__.py
 exclude_lines =
     # Have to re-enable the standard pragma
     pragma: no cover
-    
+
 
     # Don't complain about missing debug-only code:
     if self\.debug
@@ -18,10 +18,7 @@ exclude_lines =
     raise AssertionError
     raise NotImplementedError
     raise NotImplemented
-    except NotImplementedError
-    except NotImplemented
-    except AssertionError
-    except ImportError
+    except
     pass
 
     # Don't complain if non-runnable code isn't run: