debian: Hardcode a perl:any dependency in the libdpkg-perl package

The perl policy states that lib*-perl packages have to depend on the
perl package. Depending on a perl-modules packages is currently not
possible. And dh_perl will not emit a perl:any dependency for us, so
the current best option is to just hardcode it ourselves.

Reported-by: Sven Joachim <svenjoac@gmx.de>

debian/changelog

@@ -9,8 +9,9 @@ dpkg (1.18.17) UNRELEASED; urgency=medium
     - Clarify that dpkg-buildpackage does not run «dpkg-source --before-build»
       when using the -T option. Closes: #649531
   * Packaging:
-    - Do not let dh_perl insert a dependency for libdpkg-perl, because tying
-      the modules to a specific interpreter is wrong.
+    - Do not let dh_perl insert a dependency for libdpkg-perl, because it
+      emits perl instead of perl:any. Instead hardcode a perl:any dependency
+      to comply with the perl policy and make the Multi-Arch hinter happy.
 
   [ Updated scripts translations ]
   * German (Helge Kreutzmann).

debian/control

@@ -124,6 +124,7 @@ Architecture: all
 Multi-Arch: foreign
 Depends:
  ${misc:Depends},
+ perl:any,
 # Needed for arch tuples.
  dpkg (>= 1.18.11),
 Recommends: