Disable memcache for Keystone by default.

Memcache + Keystone + WSGI/Apache seems to cause a problem where
Keystone is effectively unavailable (internal errors) for about a
minute... then it comes back by itself.

So we disable it by default.  The docs default to using it, but this is
far from the first time the doc defaults trigger bugs or are simply bad
configuration!

setup-controller.sh

@@ -189,19 +189,27 @@ if [ -z "${KEYSTONE_DBPASS}" ]; then
     elif [ $OSVERSION -le $OSKILO ]; then
 	crudini --set /etc/keystone/keystone.conf token provider \
 	    'keystone.token.providers.uuid.Provider'
-	crudini --set /etc/keystone/keystone.conf token driver \
-	    'keystone.token.persistence.backends.memcache.Token'
 	crudini --set /etc/keystone/keystone.conf revoke driver \
 	    'keystone.contrib.revoke.backends.sql.Revoke'
-	crudini --set /etc/keystone/keystone.conf memcache servers \
-	    'localhost:11211'
+	if [ $KEYSTONEUSEMEMCACHE -eq 1 ]; then
+	    crudini --set /etc/keystone/keystone.conf token driver \
+		'keystone.token.persistence.backends.memcache.Token'
+	    crudini --set /etc/keystone/keystone.conf memcache servers \
+		'localhost:11211'
+	else
+	    crudini --set /etc/keystone/keystone.conf token driver \
+		'keystone.token.persistence.backends.sql.Token'
+	fi
     else
 	crudini --set /etc/keystone/keystone.conf token provider 'uuid'
-	#crudini --set /etc/keystone/keystone.conf token driver 'memcache'
-	crudini --set /etc/keystone/keystone.conf token driver 'sql'
 	crudini --set /etc/keystone/keystone.conf revoke driver 'sql'
-	#crudini --set /etc/keystone/keystone.conf memcache servers \
-	#    'localhost:11211'
+	if [ $KEYSTONEUSEMEMCACHE -eq 1 ]; then
+	    crudini --set /etc/keystone/keystone.conf token driver 'memcache'
+	    crudini --set /etc/keystone/keystone.conf memcache servers \
+		'localhost:11211'
+	else
+	    crudini --set /etc/keystone/keystone.conf token driver 'sql'
+	fi
     fi
 
     crudini --set /etc/keystone/keystone.conf DEFAULT verbose ${VERBOSE_LOGGING}

setup-lib.sh

@@ -59,6 +59,8 @@ TOKENTIMEOUT=14400
 SESSIONTIMEOUT=14400
 CEILOMETER_USE_WSGI=0
 QUOTASOFF=1
+# Off by default; seems to cause intermittent keystone unavailability.
+KEYSTONEUSEMEMCACHE=0
 #
 # We have an 'adminapi' user that gets a random password.  Then, we have
 # the dashboard and instance password, that comes in from geni-lib/rspec as a