update arg_parser.py to fix --port argument type

[lfyzjck]

--port argument defualt type is str, this will cause a consul register error.

[coveralls]

Coverage remained the same at 78.92% when pulling bde7eea on lfyzjck:master into 0f3d1e1 on ClearcodeHQ:master.

[pwilczynskiclearcode]

default 0 ? I think it's not even possible to use such port.

[lfyzjck]

perhaps there is no default value here, argument --port still equals to 0 even leave it empty.

[swistakm]

0 to 1023 are "well known ports" but there is no document that says 0 cannot be used and it has no official protocol assigned for neither TCP nor UDP. 0 is sometimes used (unofficialy) for specifying system allocated ports

[coveralls]

Coverage remained the same at 78.92% when pulling 94aa37b on lfyzjck:master into 0f3d1e1 on ClearcodeHQ:master.

[coveralls]

Coverage remained the same at 78.92% when pulling d7abdf0 on lfyzjck:master into 0f3d1e1 on ClearcodeHQ:master.

[swistakm]

build failed due to #4

[swistakm]

someone could retry the build manually. I don't have such access rights anymore.

[lfyzjck]

can't reappear this test failure in local environment.

[pwilczynskiclearcode]

someone could retry the build manually. I don't have such access rights anymore.

I granted you access to ianitor back again.

[swistakm]

Merged and released on PyPI as 0.0.3.

@pwilczynskiclearcode thanks for access grant!
@lfyzjck thanks for your contribution!