vcl/headless: some more string cleanup

As suggested by Olivier Hallot and Lubos Lunak

Change-Id: Ie5d9f379294b004992dab0b98d6dfa4aa5456159

vcl/headless/headlessinst.cxx

@@ -88,7 +88,7 @@ void SalAbort( const OUString& rErrorText, bool bDumpCore )
 {
     OUString aError( rErrorText );
     if( aError.isEmpty() )
-        aError = OUString::createFromAscii("Unknown application error");
+        aError = "Unknown application error";
     ::fprintf( stderr, "%s\n", OUStringToOString(rErrorText, osl_getThreadTextEncoding()).getStr() );
 
     ::fprintf( stderr, "SalAbort: '%s'",
@@ -101,7 +101,7 @@ void SalAbort( const OUString& rErrorText, bool bDumpCore )
 
 const OUString& SalGetDesktopEnvironment()
 {
-    static OUString aEnv( RTL_CONSTASCII_USTRINGPARAM( "headless" ) );
+    static OUString aEnv( "headless" );
     return aEnv;
 }
 

vcl/headless/svpdummies.cxx

@@ -71,10 +71,7 @@ Rectangle SvpSalSystem::GetDisplayScreenWorkAreaPosSizePixel( unsigned int nScre
 
 OUString SvpSalSystem::GetDisplayScreenName( unsigned int nScreen )
 {
-   OUStringBuffer aBuf( 32 );
-   aBuf.appendAscii( "VirtualScreen " );
-   aBuf.append( sal_Int32(nScreen) );
-   return aBuf.makeStringAndClear();
+   return "VirtualScreen " + OUString::valueOf(sal_Int32(nScreen));
 }
 
 int SvpSalSystem::ShowNativeDialog( const OUString&, const OUString&,