[tlm_teamd]: Fix segfault, when retrying to do teamd_connect() again

[pavel-shirshov]

Fixes: sonic-net/sonic-buildimage#5755
Fixes: sonic-net/sonic-buildimage#5433

What I did
Make the destination for std::transform() to use std::back_inserter() for allocating new space for the copied objects

Why I did it
To fix a bug which causes a segfault.

How I verified it

• Manually

admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel0040      
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00E0
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00EB
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00EC
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00E5
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00E6
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00E6
7admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel00E7
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel0057
admin@str-s6100-acs-1:~$ sudo config portchannel add PortChannel0057
admin@str-s6100-acs-1:~$ ls -la /var/core
total 8
drwxr-xr-x 1 root root 4096 Oct 31 01:20 .
drwxr-xr-x 1 root root 4096 Oct 30 20:28 ..

syslog

admin@str-s6100-acs-1:~$ sudo tail -F /var/log/syslog | grep tlm_
Oct 31 01:23:21.152456 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00E0' has been added.
Oct 31 01:23:24.136100 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00EB' has been added.
Oct 31 01:23:25.226382 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00EC' has been added.
Oct 31 01:23:31.052312 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00E5' has been added.
Oct 31 01:23:34.061052 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00E6' has been added.
Oct 31 01:23:40.294726 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel00E7' has been added.
Oct 31 01:23:52.171978 str-s6100-acs-1 NOTICE teamd#tlm_teamd: :- try_add_lag: The LAG 'PortChannel0057' has been added.

• It is better to cover tlm_teamd with tests. This is ToDo: for the future.

Details if related

[pavel-shirshov]

retest this please

[lguohan]

the test failure is not related to this pr.