[bug] exec is not compitable with moby

[yyb196]

Ⅰ. Issue Description

#./docker -H unix:///run/pouchd.sock exec -i 42ed sh -c 'echo test | telnet 11.160.218.230 22'
Unrecognized input header: 84

#pouch exec -i 42ed sh -c 'echo test | telnet 11.160.218.230 22'
Trying 11.160.218.230...
Connected to 11.160.218.230.
Escape character is '^]'.
Connection closed by foreign host.

Ⅱ. Describe what happened

Ⅲ. Describe what you expected to happen

Ⅳ. How to reproduce it (as minimally and precisely as possible)

Ⅴ. Anything else we need to know?

Ⅵ. Environment:

• pouch version (use pouch version):
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others: