CAY-1827 EhCache region corresponding to a cache group loses it settings after 'removeGroup'

(cherry picked from commit 54214fb732cc8bc284c19654d72bfc71d188900d)

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1486003 13f79535-47bb-0310-9956-ffa450edef68
CAY-1827 EhCache region corresponding to a cache group loses it settings after 'removeGroup'

(cherry picked from commit 54214fb732cc8bc284c19654d72bfc71d188900d)

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1486004 13f79535-47bb-0310-9956-ffa450edef68