Use different directories for session files in integration tests (#2834)

integrations/mysql.ini.tmpl

@@ -49,6 +49,7 @@ ENABLE_FEDERATED_AVATAR = false
 
 [session]
 PROVIDER = file
+PROVIDER_CONFIG = data/sessions-mysql
 
 [log]
 MODE      = console,file

integrations/pgsql.ini.tmpl

@@ -49,6 +49,7 @@ ENABLE_FEDERATED_AVATAR = false
 
 [session]
 PROVIDER = file
+PROVIDER_CONFIG = data/sessions-pgsql
 
 [log]
 MODE = console,file