Do not use own copy of actionProxy.py use common one from dockerskeleton

[csantanapr]

We currently have our own copy of actionProxy/actionproxy.py
https://github.com/apache/incubator-openwhisk-runtime-swift/blob/master/core/actionProxy/actionproxy.py#L186

We should instead use the one from dockerSkeleton, but for swift4 we need to update dockerSkeleton to take a fourth parameter zipdest to be able to override the destination of the zip when unzipping the action.

This snippet needs to be push upstream to runtime docker and then pull down from Dockerfile

    def __init__(self, source=None, binary=None, zipdest=None):
        defaultBinary = '/action/exec'
        self.source = source if source else defaultBinary
        self.binary = binary if binary else defaultBinary
        self.zipdest = zipdest if zipdest else os.path.dirname(self.source)

Once that's availabl we can update Dockerfile with

# Add the action proxy
RUN mkdir -p /actionProxy
ADD https://raw.githubusercontent.com/apache/incubator-openwhisk-runtime-docker/dockerskeleton%401.0.0/core/actionProxy/actionproxy.py /actionProxy/actionproxy.py

[csantanapr]

Depends on apache/openwhisk-runtime-docker#13

[csantanapr]

Closed by #13