Crash on API 18 when taking a picture to update profile avatar

[bmarty]

RS: https://github.com/matrix-org/riot-android-rageshakes/issues/3485

    java.lang.IllegalStateException: Matrix can not be modified
        at android.graphics.Matrix$1.oops(Matrix.java:43)
        at android.graphics.Matrix$1.postTranslate(Matrix.java:157)
        at im.vector.activity.VectorMediasPickerActivity$10.run(VectorMediasPickerActivity.java:941)
        at android.os.Handler.handleCallback(Handler.java:615)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4745)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)