Correctly skip a bottom caption

The getArg() method stops at the first closing brace, whether it
matches the opening one or not, so properly parse the caption and
then throw it away.

src/tex2lyx/text.cpp

@@ -3903,7 +3903,7 @@ void parse_text(Parser & p, ostream & os, unsigned flags, bool outer,
 			} else {
 				// We already got the caption at the bottom,
 				// so simply skip it.
-				p.getArg('{', '}');
+				parse_text_snippet(p, FLAG_ITEM, false, context);
 			}
 		}