Fix syntax error. Damn.

Signed-off-by: Maximilian Wilhelm <max@rfc2324.org>

bird/bogon_unreach.conf

@@ -1,7 +1,7 @@
 # Add unreachable routes for any prefix we don't want to route to
 # the internet.
 protocol static bogon_unreach {
-{%- if proto = 'v4' %}
+{%- if proto == 'v4' %}
 	# RFC1918, RFC 6598, APIPA, TEST nets, and stuff
 	route 0.0.0.0/8		unreachable;	# Host-Subnet
 	route 10.0.0.0/8	unreachable;	# RFC 1918