smart-attach-daemon errors when the pidfile is not available

[xrmx]

With uwsgi-1.4 branch as 092767c with this configuration:

smart-attach-daemon = /proc/unbit/tmp/memcached.pid memcached -s %d/memcached.socket -d -P /proc/unbit/tmp/memcached.pid

if the pid file does not exists it loops here:

[uwsgi-daemons] found changed pidfile for "memcached -s %d/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -u toret" (old_pid: 0 new_pid: -1)
open("/proc/unbit/tmp/memcached.pid"): No such file or directory [core/daemons.c line 96]
open("/proc/unbit/tmp/memcached.pid"): No such file or directory [core/daemons.c line 96]

[xrmx]

Once i created the pidfile i'm not able to have just one instance of memcached,

[uwsgi-daemons] spawning "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50"
[uwsgi-daemons] found changed pidfile for "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" (old_pid: 30985 new_pid: -1)
[uwsgi-daemons] throttling "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" for 1 seconds
[uwsgi-daemons] found changed pidfile for "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" (old_pid: 30986 new_pid: -1)
subprocess 30985 exited with code 0
[uwsgi-daemons] throttling "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" for 2 seconds
[uwsgi-daemons] found changed pidfile for "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" (old_pid: 30989 new_pid: -1)
[uwsgi-daemons] found changed pidfile for "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" (old_pid: 30995 new_pid: 30988)
[uwsgi-daemons] throttling "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50" for 3 seconds
[uwsgi-daemons] respawning "memcached -s /www/memcached.socket -d -P /proc/unbit/tmp/memcached.pid -m 50"