staging: deploy tricot with jemalloc heap profiling

cluster/staging/app/core/deploy/tricot.hcl

@@ -24,7 +24,7 @@ job "core-tricot" {
       driver = "docker"
 
       config {
-        image = "armael/tricot:63y35616dja8wq58dhcz362xsz95jzyk-76cae34d"
+        image = "armael/tricot:jemalloc-3"
         network_mode = "host"
         readonly_rootfs = true
         ports = [ "http_port", "https_port" ]
@@ -34,6 +34,13 @@ job "core-tricot" {
         ulimit {
           nofile = "65535:65535"
         }
+        # exporting jemalloc profiles requires a
+        # writeable tmpfs
+        mount {
+          type = "tmpfs"
+          target = "/tmp"
+          readonly = false
+        }
       }
 
       resources {