ci: stop adding capabilities before running unit tests

This ensures that all tests pass (or are automatically skipped)
when run as an unprivileged user.

Change-Id: If8b66fd6555de455648576565b1c6cbd02695d1b
Refs: #3418
diff --git a/tests/test-common.hpp b/tests/test-common.hpp
index ffff22a..9ea3d3c 100644
--- a/tests/test-common.hpp
+++ b/tests/test-common.hpp
@@ -38,7 +38,7 @@
 #define SKIP_IF_NOT_SUPERUSER() \
   do { \
     if (::geteuid() != 0) { \
-      BOOST_TEST_MESSAGE("This test case needs to be run as superuser, skipping"); \
+      BOOST_WARN_MESSAGE(false, "skipping assertions that require superuser privileges"); \
       return; \
     } \
   } while (false)