CVCapture memory leak (Bug #1749)

Platform: windows7
Compiler: c++ vc2010

Sample code to repro issue:

 1#include <cv.h>
 2
 3#include <highgui.h>
 4
 5#include <opencv2/features2d/features2d.hpp>
 6#include <opencv2/highgui/highgui.hpp>
 7#include <opencv2/imgproc/imgproc_c.h>
 8
 9#include <crtdbg.h>
10#include <cassert>
11
12using namespace cv;
13
14int main ( int argc, char **argv )
15{
16    _CrtMemState state;
17    int tmpDbgFlag;
18    tmpDbgFlag = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG);
19    tmpDbgFlag |= _CRTDBG_LEAK_CHECK_DF;
20    _CrtSetDbgFlag(tmpDbgFlag);
21    _CrtSetReportMode( _CRT_ERROR, _CRTDBG_MODE_DEBUG );
22    _CrtMemCheckpoint(&state);
23
24    VideoCapture cap(0);
25    if(!cap.isOpened())
26    {
27        return -1;
28    }
29
30    _CrtMemDumpAllObjectsSince(&state);
31
32    return 0;
33}

Debug output:

....
Dumping objects ->
{293} normal block at 0x0027D910, 24 bytes long.
 Data: <              ' > CD CD CD CD CD CD CD CD CD CD CD CD 10 D9 27 00 
{290} normal block at 0x04920040, 921600 bytes long.
 Data: <                > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD 
{289} normal block at 0x04830040, 921600 bytes long.
 Data: <                > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD 
{288} normal block at 0x04740040, 921600 bytes long.
 Data: <                > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
{285} normal block at 0x0027D1D0, 20 bytes long.
 Data: < 2              > AC 32 FD 00 00 00 00 00 FF FF FF FF FF FF FF FF 
Object dump complete.
...