remove QT_QPA_PLATFORM from ubuntu-touch

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.187) UNRELEASED; urgency=low
+
+  * Removing QPA_PLATFORM_PLUGIN as it is now handled in their proper
+    packages.
+
+ -- Sergio Schvezov <sergio.schvezov@canonical.com>  Thu, 12 Sep 2013 23:25:42 +0200
+
 livecd-rootfs (2.186) saucy; urgency=low
 
   * drop phablet-team PPA sources.list entries from ubuntu-touch, since we do

live-build/ubuntu-touch/hooks/48-setup-env.chroot

@@ -14,7 +14,6 @@ ANDROID_BOOTLOGO=1
 LD_LIBRARY_PATH=/vendor/lib:/system/lib
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
 ANDROID_DATA=/data
-QT_QPA_PLATFORM=ubuntu
 QML2_IMPORT_PATH=/usr/lib/arm-linux-gnueabihf/qt5/imports
 QT_SELECT=qt5
 SHLVL=1