plugins/default: visit_rc() leaks file descriptor

This is a multi-part message in MIME format.
--------------C4E4m0wykI3n0099vk8w7qZx
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Dear LIRC maintainers,

visit_rc() opens /sys/class/rc/rc1/protocols O_RDONLY, but never closes 
it, so the file stays open forever. [fd is overwritten by another 
O_WRONLY open a few lines later; that one is closed correctly, though.]

In my case (lirc-0.10.1 on openSUSE Leap 15.4, 'irw' running, 'lircd' 
failing to open /dev/lirc1 due to permission issues), this means that 
'lircd' creates a new /sys/class/rc/rc1/protocols file descriptor every 
second, sometimes resulting in hundreds of /proc/$PID/fd/ entries.

Apparently, this was introduced by commit 06bd6d "plugins/default: Just 
check lirc protocol if read-only access (#133)." on 17-Sep-2015.

I would suggest closing fd right after reading it; please see my 
attached patch (not tested).

Best regards,
Thomas Betker
--------------C4E4m0wykI3n0099vk8w7qZx
Content-Type: text/plain; charset=UTF-8; name="fix-fd-leak.patch"
Content-Disposition: attachment; filename="fix-fd-leak.patch"
Content-Transfer-Encoding: base64

ZGlmZiAtLWdpdCBhL3BsdWdpbnMvZGVmYXVsdC5jIGIvcGx1Z2lucy9kZWZhdWx0LmMKaW5k
ZXggZjRkMDM1OTguLmIyNDEwOWQ0IDEwMDY0NAotLS0gYS9wbHVnaW5zL2RlZmF1bHQuYwor
KysgYi9wbHVnaW5zL2RlZmF1bHQuYwpAQCAtMTUxLDYgKzE1MSw3IEBAIHN0YXRpYyBpbnQg
dmlzaXRfcmMoY29uc3QgY2hhciogcmNfZGlyLCBjb25zdCBjaGFyKiBkZXZpY2UpCiAJCXJl
dHVybiAtMTsKIAl9CiAJciA9IHJlYWQoZmQsIGJ1ZmYsIHNpemVvZihidWZmKSk7CisJY2xv
c2UoZmQpOwogCWlmIChyIDwgMCkgewogCQlsb2dfZGVidWcoIkNhbm5vdCByZWFkIGZyb20g
JXMiLCBwYXRoKTsKIAkJcmV0dXJuIC0xOwo=

--------------C4E4m0wykI3n0099vk8w7qZx
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline


--------------C4E4m0wykI3n0099vk8w7qZx--