imread() cannot read jpeg files in a particular environment (Bug #69)

The function imread() doesn't work well in a particular environment.
The following example, for instance, doesn't work.
-----
#include "cv.h"
#include "highgui.h"

using namespace cv;

int main( int argc, char** argv ) {
Mat img = imread("lena.jpg");
if( !img.data ) return 1;
namedWindow("src");
imshow("src", img);
waitKey(0);
return 0;
}
----

For example, the problem occurs on Ubuntu9.10 with libjpeg and without libjasper.
(When the Linux environment has both libjpeg and libjasper, there is no problem.)
The opencv-svn (r2490 or later) tries to build the libjasper, if the library are not found.
In that case, "boolean" type is defined as "unsigned char" in jconfig.h, because "+RPCNDR_H+" are not defined on Linux.
However libjpeg (binary for Ubuntu9.10) expects boolean defined as "int".

The difference of the definition of boolean makes the difference of "sizeof(struct jpeg_decompress_struct))".
Then it causes the problem that imread("hoge.jpg") doesn't work.

Could you try attached patch?
It looks like the patch works well in my environment; opencv(r2573) and
- Ubuntu9.10, gcc-4.4.1, libjpeg62, and without libjasper,
- WindowsXP+sp3, VC++2008 Express