[resolve] Improve resolve logging.

This change improves the logging for jiri resolve command for easily
debugging.

Change-Id: I45c915331bc8972adec8cb9c7439ab64aa75f0f2
diff --git a/cipd/cipd.go b/cipd/cipd.go
index 3de93b3..b6bd71f 100644
--- a/cipd/cipd.go
+++ b/cipd/cipd.go
@@ -589,8 +589,7 @@
 		floatingRef := <-c
 		pkgs[floatingRef.pkg] = floatingRef.floating
 		if floatingRef.err != nil {
-			errBuf.WriteString(floatingRef.err.Error())
-			errBuf.WriteByte('\n')
+			errBuf.WriteString(fmt.Sprintf("error happened while checking package %q with version %q: %v\n", floatingRef.pkg.PackageName, floatingRef.pkg.VersionTag, floatingRef.err.Error()))
 		}
 	}