Fix ocl::dft error when program end on Linux

modules/ocl/src/fft.cpp

@@ -54,6 +54,9 @@ void cv::ocl::dft(const oclMat&, oclMat&, Size, int)
 {
     CV_Error(CV_StsNotImplemented, "OpenCL DFT is not implemented");
 }
+namespace cv { namespace ocl {
+    void fft_teardown(){}
+}}
 #else
 #include "clAmdFft.h"
 namespace cv

modules/ocl/src/initialization.cpp

@@ -65,6 +65,7 @@ namespace cv
 {
     namespace ocl
     {
+        extern void fft_teardown();
         /*
          * The binary caching system to eliminate redundant program source compilation.
          * Strictly, this is not a cache because we do not implement evictions right now.
@@ -877,6 +878,7 @@ namespace cv
         }
         void Info::release()
         {
+            fft_teardown();
             if(impl->oclplatform)
             {
                 impl->oclplatform = 0;