explicitly destroy httpd service ccache file during httpinstance removal

during IPA server uninstall, the httpd service ccache is not removed from
runtime directory. This file then causes server-side client install to fail
when performing subsequent installation without rebooting/recreating runtime
directories.

This patch ensures that the old httpd ccache is explicitly destroyed during
uninstallation.

https://fedorahosted.org/freeipa/ticket/4973

Reviewed-By: David Kupka <dkupka@redhat.com>

ipaplatform/base/paths.py

@@ -327,6 +327,7 @@ class BasePathNamespace(object):
     VAR_OPENDNSSEC_DIR = "/var/opendnssec"
     OPENDNSSEC_KASP_DB = "/var/opendnssec/kasp.db"
     VAR_RUN_DIRSRV_DIR = "/var/run/dirsrv"
+    KRB5CC_HTTPD = "/var/run/httpd/ipa/krbcache/krb5ccache"
     IPA_RENEWAL_LOCK = "/var/run/ipa/renewal.lock"
     SVC_LIST_FILE = "/var/run/ipa/services.list"
     IPA_MEMCACHED_DIR = "/var/run/ipa_memcached"

ipaserver/install/httpinstance.py

@@ -412,6 +412,10 @@ class HTTPInstance(service.Service):
                 root_logger.debug(error)
                 pass
 
+        # Remove the ccache file for the HTTPD service
+        ipautil.run([paths.KDESTROY, '-c', paths.KRB5CC_HTTPD], runas='apache',
+                    raiseonerr=False)
+
         # Remove the configuration files we create
         installutils.remove_file(paths.HTTPD_IPA_REWRITE_CONF)
         installutils.remove_file(paths.HTTPD_IPA_CONF)