[bug] volume name should be validated before Create

[mathspanda]

Ⅰ. Issue Description

As the title desc, volume name should be validated before Create.

Ⅱ. Describe what happened

root@lin-vm1:~# pouch volume create --name "abc def"
Name:         abc def
Scope:
Status:       map[size:]
CreatedAt:    2018-11-2 17:54:38
Driver:       local
Labels:       map[]
Mountpoint:   /var/lib/pouch/volume/abc def

Ⅲ. Describe what you expected to happen

The volume name should be "^[a-zA-Z0-9][a-zA-Z0-9_.-]$".

IⅤ. Anything else we need to know?

None

V. Environment:

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

[mathspanda]

If need, i will fix it.

[zhuangqh]

If need, i will fix it.

already fix in #2394

[mathspanda]

OK, got it.