Enable Redis use for file locking

https://docs.nextcloud.com/server/12.0/admin_manual/configuration_server/caching_configuration.html#small-organization-single-server-setup

conf/config.json

@@ -7,7 +7,15 @@
     ],
     "updatechecker": false,
     "memcache.local": "\\OC\\Memcache\\APCu",
-    "integrity.check.disabled": true
+    "integrity.check.disabled": true,
+    "filelocking.enabled": true,
+    "memcache.locking": "\\OC\\Memcache\\Redis",
+    "redis": {
+      "host": "localhost",
+      "port": "6379",
+      "timeout": "0.0",
+      "password": ""
+     }
   },
   "apps": {
     "user_ldap": {

scripts/_common.sh

@@ -3,7 +3,7 @@
 # COMMON VARIABLES
 #=================================================
 
-pkg_dependencies="php5-gd php5-json php5-intl php5-mcrypt php5-curl php5-apcu php5-imagick imagemagick acl tar smbclient"
+pkg_dependencies="php5-gd php5-json php5-intl php5-mcrypt php5-curl php5-apcu php5-redis php5-imagick imagemagick acl tar smbclient"
 
 #=================================================
 # COMMON HELPERS