redis: use the files path correctly

Recipes are not expected to set FILESPATH directly, they are
expected to use FILESEXTRAPATH.

I can see the seting of FILESPATH in this recipe only wants to
find redis-7 specific patches and files. This could be easily achieved by
using redis-7.0.11/ directory to hold all those files.

Using FILESPATH in this way removes the possibility of overriding
some files (e.g., the redis service file) from other layers via
FILESEXTRAPATH:prepend, which is kind of a common practice and is
actually working for basically all other recipes.

This is because we have:
meta/classes-global/base.bbclass:FILESPATH = "${@base_set_filespath(["${FILE_DIRNAME}/${BP}", "${FILE_DIRNAME}/${BPN}", "${FILE_DIRNAME}/files"], d)}"
And FILESEXTRAPATH is handled in base_set_filespath.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-extended/redis/redis_7.0.11.bb

@@ -6,8 +6,6 @@ LICENSE = "BSD-3-Clause"
 LIC_FILES_CHKSUM = "file://COPYING;md5=8ffdd6c926faaece928cf9d9640132d2"
 DEPENDS = "readline lua ncurses"
 
-FILESPATH =. "${FILE_DIRNAME}/${BPN}-7:"
-
 SRC_URI = "http://download.redis.io/releases/${BP}.tar.gz \
            file://redis.conf \
            file://init-redis-server \