Fix bug in tools/generate_source_docs.sh

Due to subfolder `pagoda/tools` in the path of MKDOCS_ROOT, it was the wrong
`tools` string that was removed in the script.

tools/generate_source_docs.sh

@@ -29,7 +29,7 @@ DRY_RUN="false"
 SCRIPT_PATH="$( cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 || return 1 ; pwd -P )"
 SCRIPT_FULL_PATH="${SCRIPT_PATH}/$(basename "${BASH_SOURCE[0]}")"
 
-MKDOCS_ROOT="${SCRIPT_PATH//\/tools/}"
+MKDOCS_ROOT="${SCRIPT_PATH}/../"
 MKDOCS_DEBUG_LEVEL="INFO"
 
 manpage()