CAY-1804  Serialisation of long[] type was not working correctly.

patch by      Kris Erik Schwerdt

(cherry picked from commit 8a836401f83f50f308a770fba50221c5c572b853)

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1460113 13f79535-47bb-0310-9956-ffa450edef68