shell pipe: set exit code to error if any pipe element fails

  * this was causing backup state to be reported good while tar command failed

Change-Id: Iaa9728213bbe44a8a8622e2c0ef1ad9548ccabb7
cwm: Remove hardcoded paths

Change-Id: I1874f0bbbaa81e0eea507e9d9444307191eeb753
Merge pull request #3 from CyanogenMod/cm-11.0

Sync with cyanogenmod