Explicitly using API_BASE_URL from current connection in datastore.
Explicitly using API_BASE_URL from current connection in datastore.

This can be seen as a bug-fix where a sub-class may not be able
to impact the URIs generated.

In addition, we added the (repeated) value of the base connection's
API_BASE_URL in advance of swapping it out for v1beta3.

tswast/google-cloud-python,daspecster/google-cloud-python,dhermes/google-cloud-python,tseaver/google-cloud-python,Fkawala/gcloud-python,waprin/google-cloud-python,jonparrott/gcloud-python,waprin/google-cloud-python,VitalLabs/gcloud-python,tseaver/google-cloud-python,GoogleCloudPlatform/gcloud-python,dhermes/gcloud-python,Fkawala/gcloud-python,tseaver/gcloud-python,jonparrott/gcloud-python,waprin/gcloud-python,jonparrott/google-cloud-python,googleapis/google-cloud-python,tswast/google-cloud-python,googleapis/google-cloud-python,GoogleCloudPlatform/gcloud-python,elibixby/gcloud-python,elibixby/gcloud-python,tswast/google-cloud-python,jgeewax/gcloud-python,quom/google-cloud-python,VitalLabs/gcloud-python,tartavull/google-cloud-python,quom/google-cloud-python,daspecster/google-cloud-python,tseaver/google-cloud-python,calpeyser/google-cloud-python,calpeyser/google-cloud-python,dhermes/google-cloud-python,tartavull/google-cloud-python,waprin/gcloud-python,dhermes/google-cloud-python,dhermes/gcloud-python,jonparrott/google-cloud-python,jgeewax/gcloud-python,tseaver/gcloud-python