Fix bug configuring network in debian

In debian the default awk version is mawk and does not support the
regexp [[:alnum:]]

base_deb/etc/one-context.d/00-network

@@ -114,7 +114,7 @@ EOT
 
 get_interface_mac()
 {
-    ip link show | awk '/^[0-9]+: [[:alnum:]]+:/ { device=$2; gsub(/:/, "",device)} /link\/ether/ { print device " " $2 }'
+    ip link show | awk '/^[0-9]+: [A-Za-z0-9]+:/ { device=$2; gsub(/:/, "",device)} /link\/ether/ { print device " " $2 }'
 }
 
 get_context_interfaces()