[clang-warning-fix][deprecated-increment-bool]

In file included from /oce/drv/Image/Image_DColorImage_0.cxx:
63:
/oce/src/Image/Image_GImage.gxx:904:16: warning: incrementing
 expression of type bool is deprecated [-Wdeprecated-increment-bool]                  YAxisMirror++ ;
                  ~~~~~~~~~~~^
/oce/src/Image/Image_GImage.gxx:908:16: warning: incrementing
 expression of type bool is deprecated [-Wdeprecated-increment-bool]                  XAxisMirror++ ;
                  ~~~~~~~~~~~^
/oce/src/Image/Image_GImage.gxx:927:16: warning: incrementing
 expression of type bool is deprecated [-Wdeprecated-increment-bool]
                  XAxisMirror++ ;                  ~~~~~~~~~~~^3 warnings generated.
[clang-warning-fix][deprecated-increment-bool]

This commit fixes the warning reported by clang-3.4:
oce/src/BRepAlgo/BRepAlgo_Tool.cxx:90:9: warning: incrementing expression of type bool is deprecated [-Wdeprecated-increment-bool]
          NbSub++;
Merge pull request #404 from tpaviot/review/standard-bool-warning-fix

Clang warning fix : deprecated-increment-bool