BUG: Memory leak introduced.

In git commit 5f1e8745fe68764273533693ae6624d4cafb1c42
a memory leak was introduced.

This patch clears that memory leak, and pushes the incorrect
constructor that had potentially dangerous use cases into
the ITK_FUTURE_DEPRECATED state.

Change-Id: I11a576389ee6fb9eb09793d2811d2291a7b72325
Merge topic 'ValgrindPatch'

2714a3b6 BUG: Memory leak introduced.