Do not compile tests when vendoring

Test may fail to compile due to loopdev crate FTBFS.
See stratis-storage/project#607

Signed-off-by: mulhern <amulhern@redhat.com>

mockbuild_test/stratisd.spec

@@ -121,9 +121,12 @@ a2x -f manpage docs/stratis-dumpmetadata.txt
 
 %if %{with check}
 %check
-%if 0%{?rhel}
-%cargo_test --no-run
-%else
+# Compile stratisd tests only where package does not use vendoring.
+# This is a temporary step, to address the problem of loopdev crate
+# 0.4.0 failing to build properly in some situations due to a failure of
+# bindgen 0.59.0.
+# See https://github.com/stratis-storage/project/issues/607
+%if !0%{?rhel}
 %cargo_test -- --no-run
 %endif
 %endif