set_ca_cert
Description:
Reads a certificate from disk and sets the ca_cert property with the raw certificate data if using the nm_setting_802_1x_ck_scheme_blob scheme, or with the path to the certificate file if using the nm_setting_802_1x_ck_scheme_path scheme.
Parameters:
| this | the Setting8021x | 
| value | when  | 
| scheme | desired storage scheme for the certificate | 
| out_format | on successful return, the type of the certificate added | 
Returns:
| true if the operation succeeded, false if it was unsuccessful |