Revert "Use separate krb5 cache for backups"

This reverts commit 89f556a02c1ff553dd397c688b4c86b19f2e1cba.
diff --git a/backupninja/files/gss_kdestroy b/backupninja/files/gss_kdestroy
index 745df1c..1733cf4 100644
--- a/backupninja/files/gss_kdestroy
+++ b/backupninja/files/gss_kdestroy
@@ -1,3 +1,2 @@
-export KRB5CCNAME=/tmp/krb5cc_backupninja
 kdestroy
 
diff --git a/backupninja/files/gss_kinit b/backupninja/files/gss_kinit
index 6ac9044..8eec1b3 100644
--- a/backupninja/files/gss_kinit
+++ b/backupninja/files/gss_kinit
@@ -1,4 +1,3 @@
 {%- from "backupninja/map.jinja" import client with context -%}
-export KRB5CCNAME=/tmp/krb5cc_backupninja
 kinit -kt {{ client.target.auth.gss.get("keytab", "/etc/krb5.keytab") }} {{ client.target.auth.gss.get("principal", "host/$(hostname -f)") }}