[Ayatana] message indicator.(colour palette)

[dani planas armangue <daniplanas.a@xxxxxxxxx>]

I have noticed that the icons are nice and simple monochrome, but adding
the color, designers do not take into account the color palette.

Tango team, (which have been derived, elementary and Humanity) is a team
that has spent many years designing icons for the gnome usability. and
they know very well that the color palette of all the icons should be
consistent and not saturated.

i changes de green tone to indicator-messages-new. 
what do you think?

Attachment: indicator-messages-new.svg
Description: image/svg