dpkg: Do not check for presence of update-rc.d

It's not really needed for dpkg correct operation.

debian/changelog

@@ -16,6 +16,8 @@ dpkg (1.16.0) UNRELEASED; urgency=low
   * Count “conffile name is duplicated” for dpkg-deb warning count summary.
   * Improve and clarify strings for translation. Closes: #604914
   * Prefix all fatal error messages with “error: ”.
+  * Do not check presence of update-rc.d in the PATH in dpkg, as it's not
+    a program needed for dpkg correct operation.
 
   [ Raphaël Hertzog ]
   * Fail properly when debian/source/format is empty. Closes: #600854

src/help.c

@@ -94,7 +94,6 @@ void checkpath(void) {
 #if WITH_START_STOP_DAEMON
     "start-stop-daemon",
 #endif
-    "update-rc.d",
     NULL
   };