vl.c: call bdrv_init_with_whitelist() before cmdline parsing

commit 4d454574 "qemu-option: move standard option definitions
out of qemu-config.c" broke support for commandline option
groups that where registered during bdrv_init(). In particular
support for -iscsi options was broken since that commit.

Fix by moving the bdrv_init_with_whitelist() before command
line argument parsing.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

vl.c

@@ -2941,6 +2941,8 @@ int main(int argc, char **argv, char **envp)
     nb_numa_nodes = 0;
     nb_nics = 0;
 
+    bdrv_init_with_whitelist();
+
     autostart= 1;
 
     /* first pass of option parsing */
@@ -4199,8 +4201,6 @@ int main(int argc, char **argv, char **envp)
 
     cpu_exec_init_all();
 
-    bdrv_init_with_whitelist();
-
     blk_mig_init();
 
     /* open the virtual block devices */