fix: correctly claim capability for mock module, handle genesis expor…

…ts (#921) (#922)

## Description

This contains two fixes:
- the capability being claimed by the scoped keeper was incorrect (mock.ModuleName -> port ID)
- the mock module wasn't accounting for non empty genesis state in capabilities (after genesis export, capability will create the bound ports so rebinding doesn't need to happen)

closes: #XXXX

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [ ] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

(cherry picked from commit afa2d90)

Co-authored-by: colin axnér <25233464+colin-axner@users.noreply.github.com>

testing/mock/mock.go

@@ -43,6 +43,7 @@ var _ porttypes.IBCModule = IBCModule{}
 // PortKeeper defines the expected IBC port keeper
 type PortKeeper interface {
 	BindPort(ctx sdk.Context, portID string) *capabilitytypes.Capability
+	IsBound(ctx sdk.Context, portID string) bool
 }
 
 // AppModuleBasic is the mock AppModuleBasic.
@@ -123,10 +124,10 @@ func (am AppModule) RegisterServices(module.Configurator) {}
 // InitGenesis implements the AppModule interface.
 func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, data json.RawMessage) []abci.ValidatorUpdate {
 	for _, ibcApp := range am.ibcApps {
-		if ibcApp.PortID != "" {
+		if ibcApp.PortID != "" && !am.portKeeper.IsBound(ctx, ibcApp.PortID) {
 			// bind mock portID
 			cap := am.portKeeper.BindPort(ctx, ibcApp.PortID)
-			ibcApp.ScopedKeeper.ClaimCapability(ctx, cap, host.PortPath(ModuleName))
+			ibcApp.ScopedKeeper.ClaimCapability(ctx, cap, host.PortPath(ibcApp.PortID))
 		}
 	}