Use the same style for exception messages
diff --git a/vncviewer/OSXPixelBuffer.cxx b/vncviewer/OSXPixelBuffer.cxx
index df82c86..a3ee9d0 100644
--- a/vncviewer/OSXPixelBuffer.cxx
+++ b/vncviewer/OSXPixelBuffer.cxx
@@ -47,7 +47,7 @@
 
   data = new rdr::U8[width * height * format.bpp/8];
   if (data == NULL)
-    throw rfb::Exception(_("Error: Not enough memory for framebuffer"));
+    throw rfb::Exception(_("Not enough memory for framebuffer"));
 
   lut = CGColorSpaceCreateDeviceRGB();
   assert(lut);