ioxr - add feature_list to list to ignore

[thezoggy]

on iox 7.8.x "feature_list" is another file showing up on flash that keeps getting updated just like the nvgen_bkup.log https://github.com/haussli/rancid/blob/master/lib/iosxr.pm.in#L656-L659

sample noise:

diff --git a/configs/r16.labxtx03.us.bb.gin.ntt.net b/configs/r16.labxtx03.us.bb.gin.ntt.net
index 8886c2d74..3d647dd13 100644
- -- a/configs/r16.labxtx03.us.bb.gin.ntt.net
@@ -518,12 +518,12 @@
  !Flash: harddisk: -rw-rw-rw-. 1       1620 Feb  7 22:25 debug_shell_client.log
  !Flash: harddisk: drwxrwxrwx. 2       4096 May 17  2022 dumper
  !Flash: harddisk: -rw-r--r--. 1      20132 Jul  7  2022 enc_error_20220707_205840.log
- !Flash: harddisk: -rw-rw-rw-. 1        387 Mar 22 22:31 feature_list
+ !Flash: harddisk: -rw-rw-rw-. 1        387 Mar 22 23:31 feature_list
  !Flash: harddisk: drwx------. 3       4096 Feb  7 22:26 ima
  !Flash: harddisk: drwx------. 2      16384 May 17  2022 lost+found
  !Flash: harddisk: drwxrwxrwx. 3       4096 May 17  2022 mirror
  !Flash: harddisk: drwxrwxrwx. 2       4096 Mar 21 08:09 npu_sdk_logs
- !Flash: harddisk: -rw-rw-rw-. 1    8389113 Mar 22 22:38 nvgen_bkup.log
+ !Flash: harddisk: -rw-rw-rw-. 1    8389113 Mar 22 23:33 nvgen_bkup.log
  !Flash: harddisk: drwxrwxrwx. 2       4096 May 17  2022 nvram
  !Flash: harddisk: drwxr-xr-x. 3       4096 May 17  2022 pam

[fenrus]

I think i've patched this, feel free to verify it:

https://github.com/fenrus/rancid/commit/f2f367eed918eae851f9b00298ff86413e8234f9