envsetup: add quotes around PROMPT_COMMAND

Better compatibility for zsh.

Change-Id: Ie010c30580e67e3b5357e3cc869114a525762677
Merge "envsetup: add quotes around PROMPT_COMMAND" into cm-10.1
Merge remote-tracking branch 'cm/cm-10.1'
enable bionic optimizations for cortex-a5

Change-Id: I43742246586066352428a50e8008d6740919c929