Switch functions fetchTarget and pushChange from execPassthru to execxLocal
Reason because it kept failing with this error
$ arc land
Landing current branch 'master'.
TARGET Landing onto "master", selected by following tracking branches upstream to the closest remote.
REMOTE Using remote "origin", selected by following tracking branches upstream to the closest remote.
FETCH Fetching origin/master...
Failed to passthru proc_open(): proc_open(): CreateProcess failed, error code - 87
(Run with --trace for a full exception trace.)
When running arc diff or arc land
With this fix applied to be able to do arc land you have to do arc diff first then arc land or else
you will get the revision does not exist.