Check for errors on restic backup command (#2863)

* Check for errors on restic backup command
Signed-off-by: Dylan Murray <dymurray@redhat.com>

* Add changelog
Signed-off-by: Dylan Murray <dymurray@redhat.com>

changelogs/unreleased/2863-dymurray

+Check for errors on restic backup command

pkg/restic/exec_commands.go

@@ -90,7 +90,10 @@ func RunBackup(backupCmd *Command, log logrus.FieldLogger, updateFunc func(veler
 	cmd.Stdout = stdoutBuf
 	cmd.Stderr = stderrBuf
 
-	cmd.Start()
+	err := cmd.Start()
+	if err != nil {
+		return stdoutBuf.String(), stderrBuf.String(), err
+	}
 
 	go func() {
 		ticker := time.NewTicker(backupProgressCheckInterval)
@@ -120,7 +123,10 @@ func RunBackup(backupCmd *Command, log logrus.FieldLogger, updateFunc func(veler
 		}
 	}()
 
-	cmd.Wait()
+	err = cmd.Wait()
+	if err != nil {
+		return stdoutBuf.String(), stderrBuf.String(), err
+	}
 	quit <- struct{}{}
 
 	summary, err := getSummaryLine(stdoutBuf.Bytes())