block: remove BLOCK_OPT_NOCOW from vpc_create_opts

In commit fef6070e, the need for NOCOW was removed from the vpc driver,
as we removed the the posix calls.  However, the BLOCK_OPT_NOCOW was not
removed from vpc_create_opts.  This was a mistake - remove the opt from
there as well.
Signed-off-by: NJeff Cody <jcody@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NStefan Weil <sw@weilnetz.de>
Message-id: 8ba076fa725fed681cde7d8afc4fb239ae06a9c6.1417620301.git.jcody@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/vpc.c

@@ -893,11 +893,6 @@ static QemuOptsList vpc_create_opts = {
                 "Type of virtual hard disk format. Supported formats are "
                 "{dynamic (default) | fixed} "
         },
-        {
-            .name = BLOCK_OPT_NOCOW,
-            .type = QEMU_OPT_BOOL,
-            .help = "Turn off copy-on-write (valid only on btrfs)"
-        },
         { /* end of list */ }
     }
 };