Added a new icon for Remove Error Bars on the graph menu

To Test:
1. Start Mantidplot, load some data and create a line graph
1. With the graph selected open the graph menu
1. the Add error bars and remove error bars icons should be different and make sense.

re #3812

Code/Mantid/MantidPlot/src/ApplicationWindow.cpp

@@ -12783,7 +12783,7 @@ void ApplicationWindow::createActions()
   actionAddErrorBars->setShortcut( tr("Ctrl+B") );
   connect(actionAddErrorBars, SIGNAL(activated()), this, SLOT(addErrorBars()));
 
-  actionRemoveErrorBars = new QAction(QIcon(getQPixmap("errors_xpm")), tr("Remove Error Bars..."), this);
+  actionRemoveErrorBars = new QAction(QIcon(getQPixmap("errors_remove_xpm")), tr("Remove Error Bars..."), this);
   //actionRemoveErrorBars->setShortcut( tr("Ctrl+B") );
   connect(actionRemoveErrorBars, SIGNAL(activated()), this, SLOT(removeErrorBars()));
 

Code/Mantid/MantidPlot/src/pixmaps.cpp

@@ -8477,6 +8477,30 @@ static const char *errors_xpm[]={
 " . ",
 "..."};
 
+/* XPM */
+static const char *errors_remove_xpm[]={
+/* width height num_colors chars_per_pixel */
+"11 11 5 1",
+/* colors */
+"  c None",
+". c #000000",
+"X c #ff6666",
+"o c #ff0000",
+"O c #980000",
+/* pixels */
+"    ...  Xo",
+"     .  XoX",
+"     . XoX ",
+"     .XoX  ",
+"    .OoX   ",
+"    OoO    ",
+"   XoO.    ",
+"  XoX.     ",
+" XoX .     ",
+"XoX  .     ",
+"oX  ...    "
+};
+
 static const char *curves_xpm[]={
 "14 16 5 1",
 "   c None",
@@ -12902,6 +12926,7 @@ QPixmap getQPixmap(const std::string &name)
   else if (name == "logo_xpm") return QPixmap(logo_xpm);
   else if (name == "hand_xpm") return QPixmap(hand_xpm);
   else if (name == "errors_xpm") return QPixmap(errors_xpm);
+  else if (name == "errors_remove_xpm") return QPixmap(errors_remove_xpm);
   else if (name == "curves_xpm") return QPixmap(curves_xpm);
   else if (name == "arrow_xpm") return QPixmap(arrow_xpm);
   else if (name == "legend_xpm") return QPixmap(legend_xpm);