dpkg-query: Do not incorrectly trim package summary on --list

When computing the longest package description, the code was using
always the first package passed to list1package. Which made it trim to
an incorrect size.

debian/changelog

@@ -78,6 +78,8 @@ dpkg (1.15.8) UNRELEASED; urgency=low
     renaming if it does not. Closes: #550252
     As a side effect, this avoids useless errors when the destination
     directory is not existent or writable. Closes: #581544
+  * Properly compute the longest package description from all to be displayed
+    on “dpkg-query --list”, so that it does not get incorrectly trimmed.
 
   [ Updated programs translations ]
   * Catalan (Guillem Jover).

src/query.c

@@ -91,7 +91,7 @@ list1package(struct pkginfo *pkg, bool *head, struct pkg_array *array)
 	plen = strlen(array->pkgs[i]->name);
 	vlen = strlen(versiondescribe(&array->pkgs[i]->installed.version,
 	                              vdew_nonambig));
-	pkg_summary(pkg, &dlen);
+	pkg_summary(array->pkgs[i], &dlen);
 
 	if (plen > nw) nw = plen;
 	if (vlen > vw) vw = vlen;