ui/cocoa: Fix code for starting QEMU via image file load dialog

ui/cocoa: Fix code for starting QEMU via image file load dialog

Fix a number of bugs in the code for starting QEMU via the image
file load dialog:
 * use the actual argv[0] rather than "qemu": this avoids failures to
   find BIOS image files caused by not looking in the correct directory
   relative to the executable path
 * allocate a large enough argv array to NULL terminate it
 * use g_strdup(X) rather than g_strdup_printf("%s", X) or
   g_strdup_printf(X)
 * disable the printing of the simulated command line argument
   (which is presumably intended for debug only)

Signed-off-by: Peter Maydell <[email protected]>
Message-id: 1386543546[email protected]