fritzing.pro: remove outdated comment

Last commit that changed these lines -- b99c74c -- just fixed
whitespace errors. In fact it seems that these plugins were abandoned
in pre-git era.

phoenix.pro

@@ -28,12 +28,6 @@ lessThan(QT_MAJOR_VERSION, 5) {
     error(Fritzing does not build with Qt 4 or earlier)
 }
 
-# Fritzing requires two Qt-provided plugins in order to run correctly,
-# however the QTPLUGIN syntax only seems to work if Qt is built statically,
-# so QTPLUGIN is included here only for information purposes:
-#
-# QTPLUGIN  += qjpeg qsqlite
-
 CONFIG += debug_and_release
 
 unix:!macx {