Multiple lintian warning fixes

unknown-section varnish-6.0/web
  Section: @SECTION@/web -> Section: web
  Section: @SECTION/libdevel -> libdevel
  The substitution line in the package-deb script got removed:
  sed -i -e "s|@SECTION@|varnish-$MAJOR|" "$DIST_DIR/debian/control

copyright-without-copyright-notice:
  The copyright file expected a certain 3 line header:
      Copyright YYYY Firstname Lastname <address@example.com>
      Copr. YYYY-YYYY Firstname Lastname <address@example.com>
      © YYYY,YYYY Firstname Lastname <address@example.com>

Added debian/source/format file with content "1.0"

debian/control

 Source: varnish
-Section: @SECTION@/web
+Section: web
 Priority: optional
 Maintainer: Varnish Software <opensource@varnish-software.com>
 Build-Depends:
@@ -58,7 +58,7 @@ Description: state of the art, high-performance web accelerator
   * Graceful handling of "dead" backends
 
 Package: varnish-dev
-Section: @SECTION@/libdevel
+Section: libdevel
 Architecture: any
 Depends:
  ${shlibs:Depends},

debian/copyright

+Copyright (c) 2006 Verdens Gang AS
+Copyright (c) 2006-2018 Varnish Software AS
+All rights reserved.
+
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

debian/source/format

+1.0

package-deb

@@ -61,7 +61,6 @@ FULL_VERSION="$VERSION${RELEASE:+~}$RELEASE-$DEBVERSION"
 
 cp -r -L ../debian "$DIST_DIR"/
 
-sed -i -e "s|@SECTION@|varnish-$MAJOR|" "$DIST_DIR/debian/control"
 sed -i -e "s|@VERSION@|$FULL_VERSION|"  "$DIST_DIR/debian/changelog"
 
 tar zcf "$DIST_DIR.orig.tar.gz" "$DIST_DIR"/