Merge lp:~adam-collard/software-properties/document-update-flag into lp:software-properties

[Adam Collard]

Document the --update flag of `add-apt-repository` in it's man page.

=== modified file 'debian/changelog'
--- debian/changelog	2017-04-10 21:33:20 +0000
+++ debian/changelog	2017-07-31 10:20:43 +0000
@@ -1,3 +1,10 @@
+software-properties (0.96.24.14) artful; urgency=medium
+
+  * debian/manpages/add-apt-repository.1: Documented --update option
+    (LP: #1559482)
+
+ -- Adam Collard <[e-mail]>  Fri, 28 Jul 2017 17:15:30 +0100
+
 software-properties (0.96.24.13) zesty; urgency=medium
 
   * software-properties-gtk: also fix the backend code to set the gnome

=== modified file 'debian/manpages/add-apt-repository.1'
--- debian/manpages/add-apt-repository.1	2013-10-16 19:54:01 +0000
+++ debian/manpages/add-apt-repository.1	2017-07-31 10:20:43 +0000
@@ -25,6 +25,9 @@
 .B -y, --yes
 Assume yes to all queries
 
+.B -u, --update
+After adding the repository, update the package cache with packages from this repository (avoids need to apt-get update)
+
 .B -k, --keyserver
 Use a custom keyserver URL instead of the default
 
@@ -51,6 +54,7 @@
 
 .SH SEE ALSO
 \fBsources.list\fR(5)
+\fBapt-get\fR(8)
 
 .SH COPYRIGHT
 This manual page was written by Chow Loong Jin <[e-mail]> for the