fix: check if context is nil before calling ctx.Deadline (#1630)

Signed-off-by: Krzysztof Jaskiewicz <krzysztof.jaskiewicz@northern.tech>

Author: kjaskiewiczz

mongo/collection.go

@@ -1200,6 +1200,11 @@ func (coll *Collection) Distinct(ctx context.Context, fieldName string, filter i
 // For more information about the command, see https://www.mongodb.com/docs/manual/reference/command/find/.
 func (coll *Collection) Find(ctx context.Context, filter interface{},
 	opts ...*options.FindOptions) (cur *Cursor, err error) {
+
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
 	// Omit "maxTimeMS" from operations that return a user-managed cursor to
 	// prevent confusing "cursor not found" errors. To maintain existing
 	// behavior for users who set "timeoutMS" with no context deadline, only
@@ -1217,10 +1222,6 @@ func (coll *Collection) find(
 	opts ...*options.FindOptions,
 ) (cur *Cursor, err error) {
 
-	if ctx == nil {
-		ctx = context.Background()
-	}
-
 	f, err := marshal(filter, coll.bsonOpts, coll.registry)
 	if err != nil {
 		return nil, err