Errors with aaa_krb5

[jake2184]

There are two bugs with aaa_krb5, which cause the role to error.

aaa_krb5 in defaults/main.yml needs to be renamed to aaa_sso_krb5 to match the var in tasks/main.yml

Then the clause when: aaa_sso_krb5 is defined on line 93 of tasks/main.yml needs to be changed to when: aaa_sso_krb5, to match the other clauses in the file.