fix supernova usage msg bug

Author: neocogent

scripts/supernova

@@ -31,7 +31,7 @@ def b58hex(s58):
 	return '%x' % num
 
 
-if len(sys.argv) < 1:
+if len(sys.argv) < 2:
 	print "Usage: %s <desired address>\n" % sys.argv[0]
 	sys.exit(1)