Queues: specifying a path parameter

[tombuildsstuff]

Turns out that https://github.com/Azure/go-autorest doesn't automatically specify a path of / if one isn't specified - which means the strings computed for the authentication header can be wrong - since we were producing:

GET

application/xml; charset=utf-8

x-ms-date:Wed, 21 Aug 2019 11:53:48 GMT
x-ms-version:2018-11-09
/unlikely23exst2accti1t0?comp=properties

when Azure was expecting:

GET

application/xml; charset=utf-8

x-ms-date:Wed, 21 Aug 2019 11:53:48 GMT
x-ms-version:2018-11-09
/unlikely23exst2accti1t0/?comp=properties

(note the missing /)

This PR adds a default path of / to the GetServiceProperties method in the QueuesClient so that this works as expected

This bug only affects when using a SharedKeyLite to authenticate, which is why we didn't see this before

[tombuildsstuff]

Confirmed this fixes hashicorp/terraform-provider-azurerm#3925 and enables fixing hashicorp/terraform-provider-azurerm#3939

[radeksimko]

Looks reasonable to me, given the limited context I have.

[invidian]

@tombuildsstuff thanks for fixing that, I was debugging it today and trying to fix it myself :)

Regarding fixing hashicorp/terraform-provider-azurerm#3925, there seems to be some other issue related to decoding the error message, which needs to be addressed as well I believe.

[tombuildsstuff]

@invidian thanks for debugging that.

With regards to parsing the error message is a bug, that's a bug in Azure/go-autorest which assumes the response is JSON rather than XML (or trying both), however since this is functional (as the error is displayed, albeit it's not overly clear) we've not gotten around to sending a PR for it just yet.

Ultimately I believe this should be fixed in hashicorp/terraform-provider-azurerm#4122 - which we're working on at the moment :)