vzmigrate: fix bashism

Ooops... commit 24a78bb3d9a introduced bashism (using == instead of =
when comparing strings in [ ]) and therefore the fix was only working
in bash not dash.

http://bugzilla.openvz.org/2316
http://bugzilla.openvz.org/2356

Reported-by: Kalin Bogatzevski <kalin@bul.net>
1 file changed