dpkg-mergechangelogs: use 7 characters for conflict markers

Reported-by: Andrew Bennetts <andrew.bennetts@canonical.com>

debian/changelog

@@ -85,6 +85,8 @@ dpkg (1.16.1) UNRELEASED; urgency=low
     Closes: #606839
   * Fix the dpkg-divert test-suite to also skip test that would fail if run
     under root. Closes: #634961
+  * Change merge conflict separators created by dpkg-mergechangelogs to match
+    the usual norm of being composed of 7 characters. LP: #815700
 
   [ Guillem Jover ]
   * Install deb-src-control(5) man pages in dpkg-dev. Closes: #620520

scripts/dpkg-mergechangelogs.pl

@@ -286,5 +286,5 @@ sub get_conflict_block($$) {
     push @b, $b if defined $b;
     @a = @{$a} if ref($a) eq "ARRAY";
     @b = @{$b} if ref($b) eq "ARRAY";
-    return ("<<<<<<", @a, "======", @b, ">>>>>>");
+    return ("<<<<<<<", @a, "=======", @b, ">>>>>>>");
 }