The default resource when connecting to a gabble server is Telepathy. This means that if you configure the same account on 2 different devices and don't set the resource (quite common as people don't know what a resource is) then you will not be able to connect from both at the same time. Using a random resource would solve this.
The attached branch implements using a random resource.
branch looks good to me
Merged, will be in telepathy-gabble 0.7.28.
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