[IndexAPI2] cbq engine panics with create index desc

_time=2017-03-04T17:15:55.337-08:00 _level=ERROR _msg= panic=runtime error: index out of range stack=goroutine 736 [running

]:

github.com/couchbase/query/execution.(*Context).Recover(0xc42129bb00)

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/context.go:454 +0xbc

panic(0x48cf200, 0x5017670)

        /Users/deepkaran/.cbdepscache/exploded/x86_64/go-1.8/go/src/runtime/panic.go:489 +0x2cf

github.com/couchbase/query/execution.(*CreateIndex).RunOnce.func1()

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/index_create.go:68 +0x493

sync.(*Once).Do(0xc4212a1550, 0xc4205cc798)

        /Users/deepkaran/.cbdepscache/exploded/x86_64/go-1.8/go/src/sync/once.go:44 +0xbe

github.com/couchbase/query/execution.(*CreateIndex).RunOnce(0xc4212a1500, 0xc42129bb00, 0x0, 0x0)

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/index_create.go:88 +0x5f

created by github.com/couchbase/query/execution.(*Authorize).RunOnce.func1

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/authorize.go:81 +0x2c6

goroutine 736 [running]:

github.com/couchbase/query/execution.(*Context).Recover(0xc42129bb00)

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/context.go:454 +0xbc

panic(0x48cf200, 0x5017670)

        /Users/deepkaran/.cbdepscache/exploded/x86_64/go-1.8/go/src/runtime/panic.go:489 +0x2cf

github.com/couchbase/query/execution.(*CreateIndex).RunOnce.func1()

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/index_create.go:68 +0x493

sync.(*Once).Do(0xc4212a1550, 0xc4205cc798)

        /Users/deepkaran/.cbdepscache/exploded/x86_64/go-1.8/go/src/sync/once.go:44 +0xbe

github.com/couchbase/query/execution.(*CreateIndex).RunOnce(0xc4212a1500, 0xc42129bb00, 0x0, 0x0)

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/index_create.go:88 +0x5f

created by github.com/couchbase/query/execution.(*Authorize).RunOnce.func1

        /Users/deepkaran/workspace/cb_spock/goproj/src/github.com/couchbase/query/execution/authorize.go:81 +0x2c6

diff --git a/execution/index_create.go b/execution/index_create.go

index e361687..1c0de6d 100644

--- a/execution/index_create.go

+++ b/execution/index_create.go

@@ -63,7 +63,7 @@ func (this *CreateIndex) RunOnce(context *Context, parent value.Value) {

                }

                if indexer2, ok := indexer.(datastore.Indexer2); ok {

-                       rangeKey := make(datastore.IndexKeys, 0, len(node.Keys()))

+                       rangeKey := make(datastore.IndexKeys, len(node.Keys()))

                        for i, term := range node.Keys() {

                                rangeKey[i] = &datastore.IndexKey{Expr: term.Expression(), Desc: term.Descending()}

                        }