cmake: Fix dcmqi packaging on Appveyor
cmake: Fix dcmqi packaging on Appveyor

Since on Appveyor:
(1) dcmqi is built against an install tree of DCMTK and ITK
(2) ITK and DCMTK are build statically
(3) CMake install rules are not available from install tree

.. this commit enables the packaging of DCMTK or ITK only if the
associated *_DIR variable corresponds to a build directory.

QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi,QIICR/dcmqi