tegra3-common: add xposed prerequisites.

PS2: Change xposed policy: Don't change label of /data/data/de.robv....
     let zygote access app_data_file instead.

PS3: Correct commit message

PS4: Update policy inline with
      http://review.cyanogenmod.org/#/c/59390/

Big thanks to rovo89, Lloir and teemo @XDA

Change-Id: Iaf16a4fbf2b395b3fcbe85eec1309558ddf7e914