[skip travis] clean up the build folder between wheel creation

Author: skvark

appveyor.yml

@@ -53,29 +53,33 @@ build_script:
 
     cd ..\..
 
-    xcopy "%APPVEYOR_BUILD_FOLDER%\opencv\build\lib\RELEASE\*.pyd" cv2
+    xcopy "%APPVEYOR_BUILD_FOLDER%\opencv\build\lib\RELEASE\cv2.pyd" cv2
 
     C:\Python27\python.exe setup.py bdist_wheel
 
     del cv2\*.pyd
+    rmdir "%APPVEYOR_BUILD_FOLDER%\build" /s /q
 
     xcopy "%APPVEYOR_BUILD_FOLDER%\opencv\build64\lib\RELEASE\*.pyd" cv2
 
     C:\Python27-x64\python.exe setup.py bdist_wheel
 
     del cv2\*.pyd
+    rmdir "%APPVEYOR_BUILD_FOLDER%\build" /s /q
 
     xcopy "%APPVEYOR_BUILD_FOLDER%\opencv\build\lib\python3\Release\*.pyd" cv2
 
     C:\Python35\python.exe setup.py bdist_wheel
 
     del cv2\*.pyd
+    rmdir "%APPVEYOR_BUILD_FOLDER%\build" /s /q
 
     xcopy "%APPVEYOR_BUILD_FOLDER%\opencv\build64\lib\python3\Release\*.pyd" cv2
 
     C:\Python35-x64\python.exe setup.py bdist_wheel
 
     del cv2\*.pyd
+    rmdir "%APPVEYOR_BUILD_FOLDER%\build" /s /q
 
 before_test:
 - cmd: >-