Merge pull request #1748 from clebertsuconic/2.4.x

https://bugzilla.redhat.com/show_bug.cgi?id=1125042 - forcing clients out when the server is stuck on delivery over OIO
HORNETQ-1379 & https://bugzilla.redhat.com/show_bug.cgi?id=1125042 - using executor on ping flushes to avoid waiting for a lock