[EFL] Fix build warnings caused by missing images attributes for default buttons
https://bugs.webkit.org/show_bug.cgi?id=114955

Patch by Krzysztof Wolanski <k.wolanski@samsung.com> on 2013-04-24
Reviewed by Gyuyoung Kim.

Added default image for each button from mediacontrol catalog.

No new tests, because there is no change in behavior.

* platform/efl/DefaultTheme/widget/mediacontrol/fullscreenbutton/fullscreen_button.edc:
* platform/efl/DefaultTheme/widget/mediacontrol/mutebutton/mute_button.edc:
* platform/efl/DefaultTheme/widget/mediacontrol/playpausebutton/playpause_button.edc:
* platform/efl/DefaultTheme/widget/mediacontrol/seekbackwardbutton/seekbackward_button.edc:
* platform/efl/DefaultTheme/widget/mediacontrol/seekforwardbutton/seekforward_button.edc:
* platform/efl/DefaultTheme/widget/mediacontrol/togglecaptionsbutton/toggle_captions_button.edc:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149026 268f45cc-cd09-0410-ab3c-d52691b4dbfc