Ranger Plugin failed to download policy when JaasConfig alone is used to set the UGI instead of Principal/Keytab

Ranger Plugin failed to download policy when JaasConfig alone is used to set the UGI instead of Principal/Keytab. This was found in KNOX/STORM plugin where they use JAASCofigSection to get the UGI. TGT which is got with this failed to renew and resulted in failure of Plugin to download new policies after TGT expiry. Solution is to get the Principal and Keytab from the JAAS config and set the UGI.