scripts/kernel_bump: Use the git index to find the needed config files

The current solution using `find` introduces a racecondition, where `find`
and `git mv` get in each others way. While this could be fixed with
more-utils sponge command (or even sort -u) to buffer the output of
find.

However, a much better approach, is to query the git index directly,
which will not change, and is far more accurate.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>

scripts/kernel_bump.sh

@@ -137,9 +137,15 @@ bump_kernel()
 		done
 	fi
 
-	find "${_target_dir}" -iname "config-${source_version}" | while read -r _config; do
-		_path="${_config%%"/config-${source_version}"}"
-		git mv "${_config}" "${_path}/config-${target_version}"
+	for _config in $(git ls-files "${_target_dir}" |
+	                 sed -n "s|^\(.*config-${source_version}\).*|\1|p" |
+	                 sort -u); do
+		if [ ! -s "${_config}" ]; then
+			continue
+		fi
+
+		_subtarget="${_config%%"/config-${source_version}"}"
+		git mv "${_config}" "${_subtarget}/config-${target_version}"
 	done
 
 	git commit \