debian/control: Bump Standards-Version to 4.1.3 and bump existing packages from the extra priority to optional as the former is deprecated

debian/changelog

@@ -12,8 +12,10 @@ nut (2.7.4-6) UNRELEASED; urgency=medium
   * debian/libnutclient0.symbols: Fix version of symbols introduced in last
     NMU
   * Add python3-nut package
+  * debian/control: Bump Standards-Version to 4.1.3 and bump existing packages
+    from the extra priority to optional as the former is deprecated
 
- -- Laurent Bigonville <bigon@debian.org>  Tue, 20 Feb 2018 12:39:12 +0100
+ -- Laurent Bigonville <bigon@debian.org>  Tue, 20 Feb 2018 12:40:56 +0100
 
 nut (2.7.4-5.1) unstable; urgency=medium
 

debian/control

@@ -24,7 +24,7 @@ Build-Depends-Indep: asciidoc (>= 8.6.3),
                      dblatex (>= 0.2.5),
                      docbook-xsl,
                      libxml2-utils
-Standards-Version: 3.9.8
+Standards-Version: 4.1.3
 Homepage: http://www.networkupstools.org/
 Vcs-Browser: https://anonscm.debian.org/gitweb/?p=collab-maint/nut.git;a=summary
 Vcs-Git: https://anonscm.debian.org/git/collab-maint/nut.git
@@ -145,7 +145,6 @@ Description: network UPS tools - XML/HTTP driver
 
 Package: nut-powerman-pdu
 Architecture: any
-Priority: extra
 Depends: nut (>= 2.4.0),
          powerman (>= 2.3.3),
          ${misc:Depends},