Fixed credentials enforcing, updated readme

Change-Id: Ibc90ed7611fbe70f343abb297d1cc8fb6a947021
diff --git a/README.rst b/README.rst
index c74a3a1..82555d0 100644
--- a/README.rst
+++ b/README.rst
@@ -675,6 +675,18 @@
             url: https://path-to-my-library
             credential_id: github
 
+ Jenkins Global env properties enforcing
+
+ .. code-block:: yaml
+
+     jenkins:
+       client:
+         globalenvprop:
+           OFFLINE_DEPLOYMENT:
+             enabled: true
+             name: "OFFLINE_DEPLOYMENT" # optional, default using dict key
+             value: "true"
+
 Usage
 =====
 
diff --git a/_states/jenkins_credential.py b/_states/jenkins_credential.py
index 22d3e72..67be9a0 100644
--- a/_states/jenkins_credential.py
+++ b/_states/jenkins_credential.py
@@ -52,7 +52,7 @@
     }
     // remove credentails with same if before created new one, if exists
     def existingCreds = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(
-        com.cloudbees.plugins.credentials.common.StandardUsernameCredentials.class,
+        com.cloudbees.plugins.credentials.common.StandardCredentials.class,
         Jenkins.instance).find{it -> it.id.equals("${name}")}
     if(existingCreds){
         store.removeCredentials(domain, existingCreds)