"show interface status <interface name>" displays port channels as well as specified interface

[daall]

Steps to reproduce the issue

1. Configure a SONiC device with port channels
2. Run the "show interface status" with a specific interface name

Describe the results you received

admin@str-s6000-on-5:~$ show interface status Ethernet4
      Interface        Lanes    Speed    MTU         Alias    Vlan    Oper    Admin            Type    Asym PFC
---------------  -----------  -------  -----  ------------  ------  ------  -------  --------------  ----------
      Ethernet4  29,30,31,32      40G   9100  fortyGigE0/4   trunk      up       up  QSFP+ or later         off
PortChannel0001          N/A      40G   9100           N/A  routed      up       up             N/A         N/A
PortChannel0002          N/A      40G   9100           N/A  routed      up       up             N/A         N/A
PortChannel0003          N/A      40G   9100           N/A  routed      up       up             N/A         N/A
PortChannel0004          N/A      40G   9100           N/A  routed      up       up             N/A         N/A

Describe the results you expected

admin@str-s6000-on-5:~$ show interface status Ethernet4
      Interface        Lanes    Speed    MTU         Alias    Vlan    Oper    Admin            Type    Asym PFC
---------------  -----------  -------  -----  ------------  ------  ------  -------  --------------  ----------
      Ethernet4  29,30,31,32      40G   9100  fortyGigE0/4   trunk      up       up  QSFP+ or later         off

Output of show version

admin@str-s6000-on-5:~$ show version

SONiC Software Version: SONiC.HEAD.4-dirty-20190809.063655
Distribution: Debian 9.9
Kernel: 4.9.0-9-2-amd64
Build commit: dea940c74
Build date: Fri Aug  9 06:43:13 UTC 2019
Built by: sonicbld@jenkins-slave-phx-1

Platform: x86_64-dell_s6000_s1220-r0
HwSKU: Force10-S6000
ASIC: broadcom

[jleveque]

Bug was introduced by #483.

[jleveque]

@tsvanduyn: Can you please fix so that if an interface name is specified on the command line, only the info for that interface is displayed?

Also, since we are now displaying PortChannel info, maybe we should think about allowing portchannel names to be entered on the command line, as well? [This can be a separate PR in the future]

[qiluo-msft]

@tsvanduyn Wait for a fix...

[wendani]

@tsvanduyn Please also update the unit test to intfutil