Fix MUnit baseline file path

The read and error message for the baseline file check in the
UnitTest.cmake.in file were not changed to use the new layout.

Use the path from the if statement to replace the references to the
UnitTest directory.

OSEHRA-Issue: http://issues.osehra.org/browse/OAT-51
Change-Id: If30c88fb499314c88d37ebc116e622de53d40675