For a failing image load, indicate theme

(only in case OSL_DEBUG_LEVEL>0)

Change-Id: I31217c72c9bddaa748a5980252b40d025c76b730
Reviewed-on: https://gerrit.libreoffice.org/27473Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

vcl/source/image/ImageList.cxx

@@ -139,6 +139,9 @@ void ImageAryData::Load(const OUString &rPrefix)
         aMessage.append( "ImageAryData::Load: failed to load image '" );
         aMessage.append( OUStringToOString( aFileName, RTL_TEXTENCODING_UTF8 ).getStr() );
         aMessage.append( "'" );
+        aMessage.append( " from icon theme '" );
+        aMessage.append( OUStringToOString( aIconTheme, RTL_TEXTENCODING_UTF8 ).getStr() );
+        aMessage.append( "'" );
         OSL_FAIL( aMessage.makeStringAndClear().getStr() );
     }
 #endif