ref-manual: Fixed style sheet

Style sheet was not spacing after the first paragraph for glossary
entries.

(From yocto-docs rev: fb08aec5303ed21315839c55b413873569497f23)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-style.css

@@ -255,7 +255,7 @@ div.variablelist dl {
 
 .glossary dd p,
 .variablelist dd p {
-  margin-top: -1.3em;
+  margin-top: 0em;
   margin-bottom: 1em;
 }