Replaced namespace UnitTests by namespace unitTests because namespaces in

castor/exception/ExceptionTest.cpp

castor/server/DaemonTest.cpp

castor/tape/tapeserver/SCSI/DeviceTest.cpp

castor/tape/tapeserver/SCSI/StructuresTest.cpp

castor/tape/tapeserver/drive/DriveTest.cpp

castor/tape/tapeserver/exception/ExceptionTest.cpp

castor/tape/tapeserver/file/StructuresTest.cpp

castor/tape/tapeserver/threading/ThreadingTests.cpp

castor/tape/tapeserver/utils/RegexTest.cpp

castor/utils/UtilsTest.cpp