Fix description of size parameter in qemu-img's help text

Valid description taken from qemu-img.texi, although it would be better
to have this information recorded in only one place.

Signed-off-by: Pierre Riteau <Pierre.Riteau@irisa.fr>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-img.c

@@ -72,9 +72,9 @@ static void help(void)
            "Command parameters:\n"
            "  'filename' is a disk image filename\n"
            "  'fmt' is the disk image format. It is guessed automatically in most cases\n"
-           "  'size' is the disk image size in kilobytes. Optional suffixes\n"
-           "    'M' (megabyte, 1024 * 1024) and 'G' (gigabyte, 1024 * 1024 * 1024) are\n"
-           "    supported any 'k' or 'K' is ignored\n"
+           "  'size' is the disk image size in bytes. Optional suffixes\n"
+           "    'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' (gigabyte, 1024M)\n"
+           "    and T (terabyte, 1024G) are supported. 'b' is ignored.\n"
            "  'output_filename' is the destination disk image filename\n"
            "  'output_fmt' is the destination format\n"
            "  'options' is a comma separated list of format specific options in a\n"