COMP: Fix QAtomicInt::load() deprecation warning in ctkErrorLogQtMessageHandler
COMP: Fix QAtomicInt::load() deprecation warning in ctkErrorLogQtMessageHandler

This commit fixes the warnings like the following reported when building
against Qt >= 5.14.

  /path/to/S-r/CTK/Libs/Core/ctkErrorLogQtMessageHandler.cpp:70:57: warning: 'load' is deprecated: Use loadRelaxed [-Wdeprecated-declarations]
    if (ctkErrorLogQtMessageHandler_CurrentRecursionDepth.load() > 10)
                                                          ^
  /path/to/Support/Qt/5.15.2/clang_64/lib/QtCore.framework/Headers/qbasicatomic.h:103:5: note: 'load' has been explicitly marked deprecated here
      QT_DEPRECATED_VERSION_X_5_14("Use loadRelaxed") T load() const noexcept { return loadRelaxed(); }
      ^
  /path/to/Support/Qt/5.15.2/clang_64/lib/QtCore.framework/Headers/qglobal.h:366:45: note: expanded from macro 'QT_DEPRECATED_VERSION_X_5_14'
  # define QT_DEPRECATED_VERSION_X_5_14(text) QT_DEPRECATED_X(text)
                                              ^
  /path/to/Support/Qt/5.15.2/clang_64/lib/QtCore.framework/Headers/qglobal.h:294:33: note: expanded from macro 'QT_DEPRECATED_X'
  #  define QT_DEPRECATED_X(text) Q_DECL_DEPRECATED_X(text)
                                  ^
  /path/to/Support/Qt/5.15.2/clang_64/lib/QtCore.framework/Headers/qcompilerdetection.h:675:55: note: expanded from macro 'Q_DECL_DEPRECATED_X'
  #    define Q_DECL_DEPRECATED_X(text) __attribute__ ((__deprecated__(text)))
                                                        ^

commontk/CTK,commontk/CTK,commontk/CTK,commontk/CTK