fix the wrong path in mkreleasehdr.sh (#12993)

The question is introduced in #12799 , the script cannot find the
correct src and deps directories, so it always returns dirty as 0.

src/mkreleasehdr.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 GIT_SHA1=`(git show-ref --head --hash=8 2> /dev/null || echo 00000000) | head -n1`
-GIT_DIRTY=`git diff --no-ext-diff -- src deps 2> /dev/null | wc -l`
+GIT_DIRTY=`git diff --no-ext-diff -- ../src ../deps 2> /dev/null | wc -l`
 BUILD_ID=`uname -n`"-"`date +%s`
 if [ -n "$SOURCE_DATE_EPOCH" ]; then
   BUILD_ID=$(date -u -d "@$SOURCE_DATE_EPOCH" +%s 2>/dev/null || date -u -r "$SOURCE_DATE_EPOCH" +%s 2>/dev/null || date -u +%s)