e2e: fix panic when checking error

fix panic during error handling

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
(cherry picked from commit 09df2c6)

e2e/utils.go

@@ -214,11 +214,14 @@ func validateOmapCount(f *framework.Framework, count int, driver, pool, mode str
 		filterLessCmds := []string{cmds.radosLsCmd, cmds.radosLsKeysCmd}
 		for i, cmd := range filterCmds {
 			stdOut, stdErr, err := execCommandInToolBoxPod(f, cmd, rookNamespace)
-			if err != nil || stdErr != "" {
+			if err != nil {
 				if !strings.Contains(err.Error(), exitOneErr) {
 					e2elog.Failf("failed to execute rados command '%s' : err=%v stdErr=%s", cmd, err, stdErr)
 				}
 			}
+			if stdErr != "" {
+				e2elog.Failf("failed to execute rados command '%s' : stdErr=%s", cmd, stdErr)
+			}
 			err = compareStdoutWithCount(stdOut, count)
 			if err == nil {
 				continue