regtest: put rgb and yuv reference files in correct place

SVN design flaw requires deleting dirs in separate step

Originally committed as revision 24117 to svn://svn.ffmpeg.org/ffmpeg/trunk

tests/ref/vsynth1/rgb/rgb.vsynth1.regression

-05f0719cb52486d9a4beb9cfae3f2571 *./tests/data/vsynth1/rgb.avi
-15213260 ./tests/data/vsynth1/rgb.avi
-243325fb2cae1a9245efd49aff936327 *./tests/data/rgb.vsynth1.out.yuv
-stddev:    3.42 PSNR: 37.43 bytes:  7603200/  7603200

tests/ref/vsynth1/yuv/yuv.vsynth1.regression

-aa6b9e862aebcf8902a6d770e7729d59 *./tests/data/vsynth1/yuv.avi
-7610060 ./tests/data/vsynth1/yuv.avi
-c5ccac874dbf808e9088bc3107860042 *./tests/data/yuv.vsynth1.out.yuv
-stddev:    0.00 PSNR:999.99 bytes:  7603200/  7603200

tests/ref/vsynth2/rgb/rgb.vsynth2.regression

-f2e9c419023c743bf99aa5b2e55ad233 *./tests/data/vsynth2/rgb.avi
-15213260 ./tests/data/vsynth2/rgb.avi
-b2418e0e3a9a8619b31219cbcf24dc82 *./tests/data/rgb.vsynth2.out.yuv
-stddev:    1.26 PSNR: 46.06 bytes:  7603200/  7603200

tests/ref/vsynth2/yuv/yuv.vsynth2.regression

-30a400773ab26f2c83e469198b156f1d *./tests/data/vsynth2/yuv.avi
-7610060 ./tests/data/vsynth2/yuv.avi
-dde5895817ad9d219f79a52d0bdfb001 *./tests/data/yuv.vsynth2.out.yuv
-stddev:    0.00 PSNR:999.99 bytes:  7603200/  7603200