Pass an explicit template to mktemp since that is required on Mac OS X.
Hardcoded to /tmp since I did not want to bother validating TMPDIR which
is user supplied.
Explicit define a repeating group which causes a grep error:
repetition-operator operand invalid
Change-Id: Ib23cc15db7f7dfdd611280884e46342562d545df
35584efa90