Please update OpenOCD
Look my config file is working correctly I'm using OS X. To test my assumption there is something wrong with openocd I used two different openocd binaries one which is most recent openocd 0.10 release, this worked correctly with connection under hardware reset. Then with pretty much the same config file openocd provided with s24stm32 fails when asserting rst and throws an error. This is obviously related to openocd version since newer works fine under the same conditions.
For temporary fix you can simply replace all the binaries and scripts under openocd plugin folder in Eclipse with new ones on openocd website.