dpkg: Shutdown the modstatdb in --get-selections

Otherwise we'll crash in commandfd.

debian/changelog

@@ -22,6 +22,7 @@ dpkg (1.18.11) UNRELEASED; urgency=medium
   * Always reset the package in-core database when shutting down the package
     database journal.
   * Do not crash if we pass a NULL cip argument to setaction() in libdpkg.
+  * Shutdown the package database journal in dpkg --get-selections.
   * Perl modules:
     - Obsolete Source-Version substvar in Dpkg::Substvars by emitting errors.
     - Rework keyring hooks in Dpkg::Vendor. Deprecate the keyrings hook, and

src/select.c

@@ -103,6 +103,8 @@ getselections(const char *const *argv)
 
   pkg_array_destroy(&array);
 
+  modstatdb_shutdown();
+
   return 0;
 }