[source] base-files: add submission service port

[LEDE Commits]

jow pushed a commit to source.git, branch lede-17.01:
https://git.lede-project.org/15efa0950714abffcfe41d81da3ca688f857eb3a

commit 15efa0950714abffcfe41d81da3ca688f857eb3a
Author: Lucian Cristian <lucian.cristian at gmail.com>
AuthorDate: Sat Mar 4 15:24:44 2017 +0200

    base-files: add submission service port
    
    prevent postfix start failure fatal: 0.0.0.0:submission: Unrecognized service
    
    Signed-off-by: Lucian Cristian <lucian.cristian at gmail.com>
    (cherry picked from commit 8e75efc0fb52d02a0cdc13a5ad819b380de6f3da)
---
 package/base-files/files/etc/services | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/package/base-files/files/etc/services b/package/base-files/files/etc/services
index a12853e..8ff914e 100644
--- a/package/base-files/files/etc/services
+++ b/package/base-files/files/etc/services
@@ -76,6 +76,8 @@ afpovertcp	548/tcp
 afpovertcp	548/udp
 nntps		563/tcp		snntp
 nntps		563/udp		snntp
+submission	587/tcp
+submission	587/udp
 ldaps		636/tcp
 ldaps		636/udp
 tinc		655/tcp