[LyX/master] Fix bug #1996

[Guillaume Munch]

commit f3008c30796167c3368042c32e4f0fbc69055de2
Author: Guillaume Munch <g...@lyx.org>
Date:   Sat Aug 29 03:38:54 2015 +0100

    Fix bug #1996
    
    \overrightarrow and related macros have a standard behaviour with respect to
    sub/superscripts.

diff --git a/src/mathed/InsetMathDecoration.cpp 
b/src/mathed/InsetMathDecoration.cpp
index 9b4a5de..b515d56 100644
--- a/src/mathed/InsetMathDecoration.cpp
+++ b/src/mathed/InsetMathDecoration.cpp
@@ -59,13 +59,7 @@ bool InsetMathDecoration::isScriptable() const
 {
        return
                        key_->name == "overbrace" ||
-                       key_->name == "underbrace" ||
-                       key_->name == "overleftarrow" ||
-                       key_->name == "overrightarrow" ||
-                       key_->name == "overleftrightarrow" ||
-                       key_->name == "underleftarrow" ||
-                       key_->name == "underrightarrow" ||
-                       key_->name == "underleftrightarrow";
+                       key_->name == "underbrace";
 }