Minor schematic formatter fix.

Apparently at some point in KiCad's development, a '~' character was
prefixed to the symbol name to indicate that it was not visible.  The
visibility state is now saved in the name field so remove the prefix.
The parser was kept unchanged.

Fixes lp:1632048

https://bugs.launchpad.net/kicad/+bug/1632048

(cherry picked from commit ee14da3093)

eeschema/sch_legacy_plugin.cpp

@@ -3584,15 +3584,7 @@ void SCH_LEGACY_PLUGIN_CACHE::saveSymbol( LIB_PART* aSymbol,
 
     // Save data
     aFormatter->Print( 0, "DEF" );
-
-    if( value.IsVisible() )
-    {
     aFormatter->Print( 0, " %s", TO_UTF8( value.GetText() ) );
-    }
-    else
-    {
-        aFormatter->Print( 0, " ~%s", TO_UTF8( value.GetText() ) );
-    }
 
     LIB_FIELD& reference = aSymbol->GetReferenceField();