[source] dnsmasq: drop --interface and --except-interface options when the interface cannot be found

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/?p=source.git;a=commitdiff;h=b2ddfbc1c7b935cf931b4c336969b65947270ce9

commit b2ddfbc1c7b935cf931b4c336969b65947270ce9
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Fri Jul 29 20:58:14 2016 +0200

    dnsmasq: drop --interface and --except-interface options when the interface cannot be found
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 package/network/services/dnsmasq/files/dnsmasq.init | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/package/network/services/dnsmasq/files/dnsmasq.init b/package/network/services/dnsmasq/files/dnsmasq.init
index 54cb0eb..2b81a61 100644
--- a/package/network/services/dnsmasq/files/dnsmasq.init
+++ b/package/network/services/dnsmasq/files/dnsmasq.init
@@ -119,12 +119,12 @@ append_ipset() {
 }
 
 append_interface() {
-	network_get_device ifname "$1"
+	network_get_device ifname "$1" || return
 	xappend "--interface=$ifname"
 }
 
 append_notinterface() {
-	network_get_device ifname "$1"
+	network_get_device ifname "$1" || return
 	xappend "--except-interface=$ifname"
 }