fs-perms: Ensure /usr/src/debug/ file modes are correct

If files are copied into /usr/src/debug directly from WORKDIR (e.g. makedevs)
we'd get the permissions from the checkout which would depend on the host umask.

Avoid this and be deterministic by setting the file modes consistently. Core
code copies the files in so we're responsible for the permissions.

Unfortunately to force this change to apply we need to invalidate both
the package tasks and the hash equivalance mappings since file mode
'corruption' already made it into the output hashes (both input options
were mapped to the output hashes).

(From OE-Core rev: 1f958bcd6c9cd12ec76d80586cba15f4d6ed17a7)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/package.bbclass

@@ -2340,7 +2340,7 @@ python do_package () {
     # cache.  This is useful if an item this class depends on changes in a
     # way that the output of this class changes.  rpmdeps is a good example
     # as any change to rpmdeps requires this to be rerun.
-    # PACKAGE_BBCLASS_VERSION = "2"
+    # PACKAGE_BBCLASS_VERSION = "4"
 
     # Init cachedpath
     global cpath