dpkg: Update list of binaries to check on PATH

Remove install-info which is now a wrapper and will disappear soonish.
Add programs used by dpkg itself: sh, rm, find, tar and dpkg-deb.

debian/changelog

@@ -2,6 +2,9 @@ dpkg (1.15.5) UNRELEASED; urgency=low
 
   [ Guillem Jover ]
   * Remove obsolete conffiles on purge. Closes: #421367, #453005, #454628
+  * Update list of binaries dpkg checks on the PATH.
+    - Remove install-info, now a wrapper that will disappear soonish.
+    - Add programs used by dpkg itself: sh, rm, find, tar and dpkg-deb.
 
   [ Raphaël Hertzog ]
   * Add versioned dependency on base-files (>= 5.0.0) to dpkg-dev to ensure

src/help.c

@@ -80,11 +80,16 @@ struct filenamenode *namenodetouse(struct filenamenode *namenode, struct pkginfo
 
 void checkpath(void) {
 /* Verify that some programs can be found in the PATH. */
-  static const char *const checklist[]= { "ldconfig", 
+  static const char *const checklist[] = {
+    DEFAULTSHELL,
+    RM,
+    TAR,
+    FIND,
+    BACKEND,
+    "ldconfig",
 #if WITH_START_STOP_DAEMON
     "start-stop-daemon",
 #endif    
-    "install-info",
     "update-rc.d",
     NULL
   };