Merge pull request openshift#2449 from ahardin-rh/cfg-secret-help

Follow-up edit to PR#2011

Author: ahardin-rh

dev_guide/managing_images.adoc

@@ -680,7 +680,7 @@ $ oc secrets new-dockercfg <secret_name> \
 For more options, see:
 
 ----
-$ oc secrets new --help
+$ oc secrets new-dockercfg --help
 ----
 
 After the secret is configured, proceed with creating the new image stream or