Changed the nomenclature of credentials command

Removed the "s" of the "credentials command" in the documentation and renaming the file to credential.rst (instead of credentials)

Change-Id: If1df15b9a630a5452e05d14fb45e9ebb124583a7

Author: dritux

…c/source/command-objects/credentials.rst doc/source/command-objects/credential.rstdoc/source/command-objects/credentials.rst renamed to doc/source/command-objects/credential.rst doc/source/command-objects/credentials.rst renamed to doc/source/command-objects/credential.rst

@@ -1,27 +1,27 @@
 ===========
-credentials
+credential
 ===========
 
 Identity v3
 
-credentials create
+credential create
 ------------------
 
 .. ''[consider rolling the ec2 creds into this too]''
 
 .. code:: bash
 
-    os credentials create
+    os credential create
         --x509
         [<private-key-file>]
         [<certificate-file>]
 
-credentials show
+credential show
 ----------------
 
 .. code:: bash
 
-    os credentials show
+    os credential show
         [--token]
         [--user]
         [--x509 [--root]]

doc/source/commands.rst

@@ -83,7 +83,7 @@ referring to both Compute and Volume quotas.
 * ``console url``: (**Compute**) server remote console URL
 * ``consumer``: (**Identity**) OAuth-based delegatee
 * ``container``: (**Object Storage**) a grouping of objects
-* ``credentials``: (**Identity**) specific to identity providers
+* ``credential``: (**Identity**) specific to identity providers
 * ``domain``: (**Identity**) a grouping of projects
 * ``ec2 credentials``: (**Identity**) AWS EC2-compatible credentials
 * ``endpoint``: (**Identity**) the base URL used to contact a specific service