Wrap changelog lines at 78 characters

This fixes lintian warnings.

debian/changelog

@@ -39,15 +39,15 @@ dpkg (1.15.0) UNRELEASED; urgency=low
   * Modified Dpkg::BuildOptions to recognize and use spaces as separator
     in DEB_BUILD_OPTIONS (in order to conform with the Debian policy
     ruling estasblished in #430649). Closes: #486937
-  * Add DEB_VENDOR environment variable in the build environment to be able to
-    change behaviour dynamically depending on the vendor of the current system
-    (or target system when the user overrides DEB_VENDOR by setting it himself).
-    Closes: #457371
+  * Add DEB_VENDOR environment variable in the build environment to be able
+    to change behaviour dynamically depending on the vendor of the current
+    system (or target system when the user overrides DEB_VENDOR by setting
+    it himself). Closes: #457371
   * dpkg-shlibdeps give less strong warnings for symbols not found in NEEDED
     libraries when the shared library is a non-public directory and is likely
     to be a plugin. Closes: #481165
-  * Clarify lisf of packages displayed by dpkg --get-selections and dpkg-query -l.
-    Thanks to Jidanni. Closes: #487455
+  * Clarify lisf of packages displayed by dpkg --get-selections and
+    dpkg-query -l. Thanks to Jidanni. Closes: #487455
   * Document -A option in dpkg-buildpackage(1). Closes: #482834
   * Add some warning concerning the available file and the related commands.
     They are mostly obsolete for APT users. Closes: #481185