How to resolve permission denied errors (Permission denied (publickey,gssapi-keyex,gssapi-with-mic))

Code: 
KB-E1015
Applies to: 
OpenShift
Issue: 

How to resolve permission denied errors errors when using git + ssh to communicate with an OpenShift application.

Resolution: 

Sometimes when creating an application you might see this error from rhc-create-app:

Checking ~/.ssh/config
Contacting https://stg.openshift.redhat.com
Found stg.rhcloud.com in ~/.ssh/config... No need to adjust
Now your new domain name is being populated worldwide (this might take a minute)...
Pulling new repo down
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
fatal: The remote end hung up unexpectedly
Error in git pull

You may also see this similar error when using git clone, or git push:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
fatal: The remote end hung up unexpectedly

These errors could mean one or more of a few things:
- You have modified your public SSH key on the Web Console on the web site and not updated the SSH keys on the machine you are executing rhc* / git from
- You have modified your SSH keys on the machine you are executing rhc* / git from and not updated your public SSH key on the Web Console on the web site
- You are using Gnome and the gnome-keyring-manager has cached the old keys.  Logging out and back in to Gnome should resolve this.  There may also be a way to restart the keyring manager w/out logging out (or flushing the cache and forcing it to rebuild).
- You can try running ssh-add as per: https://help.github.com/articles/error-agent-admitted-failure-to-sign