ticket:10017: Remove formatTimePeriod from C++ TimeUnitFormat class.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33639 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10017: Fixed broken compile in C++.

git-svn-id: http://source.icu-project.org/repos/icu/icu/branches/tkeep@33640 251d0590-4201-4cf1-90de-194747b24ca1