Refactor _blog_index function in qsgen2 script

- Change the debug message to use  instead of
- Update the echo command to use double quotes around

These changes improve the readability and consistency of the code.

qsgen2

@@ -917,9 +917,9 @@ function _blog_index() {
     if (${debug}); then
       _msg debug "_blog_index: Writing ${www_root}/blog/index.html"
       _msg debug "_blog_index: Content of blog_index_content"
-      _msg info "${blog_index_content}"
+      _msg sub "${blog_index_content}"
     fi
-    echo "${blog_index_content}" > ${www_root}/blog/index.html
+    echo "$blog_index_content" > ${www_root}/blog/index.html
     _f_last_updated ${www_root}/blog/index.html
   fi