Create MemcacheTest.php
Added test cases with lifetime 60*5 and 60*50

Adding test cases of the bug 4101

http://dev.kohanaframework.org/issues/4101

These tests are running successfully
Merge pull request #45 from enov/3.2/bug/4101-memcache-lifetime

3.2/bug/4101 memcache lifetime

refs #4101