Comment 2 for bug 1543216

Although, this one in particular is even more awesome, because we get a panic as a result of trying to store the charm after the connection is shut down:

2016-02-08 15:12:49 DEBUG juju.storage managedstorage.go:294 managed resource entry created with path "buckets/b35686de-5f09-4e7e-8f9f-dae388a3d5c0/charms/local:trusty/dummy-sink-0-95f8f94d-f7d0-4f0f-8c4f-b7426a8efaa1" -> "1aa8fc4f7ab2ee3c0c00fbd9846fd89336d70710247e5d7a548a8e65698031d23269598f92c5c0279a97113a6b912afd"
2016/02/08 15:12:49 http: panic serving 10.0.210.1:57604: Session already closed
goroutine 865 [running]:
net/http.func·009()
 /usr/lib/go/src/pkg/net/http/server.go:1093 +0xae
runtime.panic(0x16617a0, 0xc210794e30)
 /usr/lib/go/src/pkg/runtime/panic.c:248 +0x106
gopkg.in/mgo%2ev2.(*Session).cluster(0xc21025f540, 0x1c)
 /workspace/juju-core-2.0-alpha2/src/gopkg.in/mgo.v2/session.go:1549 +0x66
gopkg.in/mgo%2ev2.copySession(0xc21025f540, 0x424e01, 0xc21000f000)
 /workspace/juju-core-2.0-alpha2/src/gopkg.in/mgo.v2/session.go:519 +0x32
gopkg.in/mgo%2ev2.(*Session).Copy(0xc21025f540, 0x4d544b0)
 /workspace/juju-core-2.0-alpha2/src/gopkg.in/mgo.v2/session.go:1515 +0x41
github.com/juju/juju/mongo.CollectionFromName(0xc210349520, 0x2156ee0, 0x6, 0x6, 0xc2103504a8, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/mongo/collections.go:12 +0x35
github.com/juju/juju/state.(*database).GetCollection(0xc2102fad40, 0x2156ee0, 0x6, 0x0, 0x0, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/state/database.go:182 +0x3c0
github.com/juju/juju/state.(*State).getCollection(0xc2100a44d0, 0x2156ee0, 0x6, 0xc210622108, 0x6bcc1d, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/state/collection.go:22 +0x44
github.com/juju/juju/state.(*State).UpdateUploadedCharm(0xc2100a44d0, 0x7f8ef8029230, 0xc2106aca50, 0xc21038e000, 0xc210690910, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/state/state.go:1074 +0x6f
github.com/juju/juju/apiserver/service.StoreCharmArchive(0xc2100a44d0, 0xc21038e000, 0x7f8ef8029230, 0xc2106aca50, 0x7f8efb6e7618, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/apiserver/service/charmstore.go:137 +0x206
github.com/juju/juju/apiserver.(*charmsHandler).repackageAndUploadCharm(0xc2102a2340, 0xc2100a44d0, 0xc2106aca50, 0xc21038e000, 0x0, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/apiserver/charms.go:387 +0x561
github.com/juju/juju/apiserver.(*charmsHandler).processPost(0xc2102a2340, 0xc210873820, 0xc2100a44d0, 0x0, 0x0, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/apiserver/charms.go:253 +0x71a
github.com/juju/juju/apiserver.(*charmsHandler).servePost(0xc2102a2340, 0x7f8efb6e7350, 0xc2102138c0, 0xc210873820, 0xc2106ac701, ...)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/apiserver/charms.go:66 +0xa7
github.com/juju/juju/apiserver.(*charmsHandler).ServeHTTP(0xc2102a2340, 0x7f8efb6e7350, 0xc2102138c0, 0xc210873820)
 /workspace/juju-core-2.0-alpha2/src/github.com/juju/juju/apiserver/charms.go:48 +0x177
github.com/bmizerany/pat.(*PatternServeMux).ServeHTTP(0xc21018b410, 0x7f8efb6e7350, 0xc2102138c0, 0xc210873820)
 /workspace/juju-core-2.0-alpha2/src/github.com/bmizerany/pat/mux.go:109 +0x1be
net/http.serverHandler.ServeHTTP(0xc210110910, 0x7f8efb6e7350, 0xc2102138c0, 0xc210873820)
 /usr/lib/go/src/pkg/net/http/server.go:1597 +0x16e
net/http.(*conn).serve(0xc210313600)
 /usr/lib/go/src/pkg/net/http/server.go:1167 +0x7b7
created by net/http.(*Server).Serve
 /usr/lib/go/src/pkg/net/http/server.go:1644 +0x28b