tools/syz-covermerger: more logs

I don't see any visible problems but the records in DB are not created.
Let's report the amount of records created at the end of the batch step.

+log the names of the managers

1 files changed, 8 insertions, 2 deletions

diff --git a/dashboard/dashapi/dashapi.go b/dashboard/dashapi/dashapi.go
index 9e1d29d0b..8133d47c5 100644
--- a/dashboard/dashapi/dashapi.go
+++ b/dashboard/dashapi/dashapi.go
@@ -704,8 +704,14 @@ type SaveCoverageReq struct {
 	Coverage *MergedCoverage
 }
 
-func (dash *Dashboard) SaveCoverage(req *SaveCoverageReq) error {
-	return dash.Query("save_coverage", req, nil)
+// SaveCoverage returns amount of records created in db.
+func (dash *Dashboard) SaveCoverage(req *SaveCoverageReq) (int, error) {
+	resp := new(int)
+	if err := dash.Query("save_coverage", req, resp); err != nil {
+		return 0, err
+	} else {
+		return *resp, err
+	}
 }
 
 type TestPatchRequest struct {