Searched executables from the current working directory.
Searched executables from the current working directory.

If a framework specifies use of its own executor (in the sandbox) and
sets shell to false, the executor is never found. This is becase if
the PATH env variable is set, `execvp` or `execvpe` won't look into
the current working directory for executables. This patch adds the
support for searching the current working directory for executables.

Review: https://reviews.apache.org/r/60280/

zmalik/mesos,zmalik/mesos,neilconway/mesos,gsantovena/mesos,gsantovena/mesos,gsantovena/mesos,jpeach/mesos,kaysoky/mesos,kaysoky/mesos,Gilbert88/mesos,Gilbert88/mesos,chhsia0/mesos,gsantovena/mesos,zmalik/mesos,reneploetz/mesos,andschwa/mesos,reneploetz/mesos,reneploetz/mesos,andschwa/mesos,neilconway/mesos,abudnik/mesos,kaysoky/mesos,reneploetz/mesos,asamerh4/mesos,Gilbert88/mesos,asamerh4/mesos,jpeach/mesos,Gilbert88/mesos,chhsia0/mesos,abudnik/mesos,jpeach/mesos,asamerh4/mesos,andschwa/mesos,verizonlabs/mesos,jpeach/mesos,dforsyth/mesos,Gilbert88/mesos,reneploetz/mesos,neilconway/mesos,dforsyth/mesos,zmalik/mesos,chhsia0/mesos,neilconway/mesos,abudnik/mesos,asamerh4/mesos,abudnik/mesos,neilconway/mesos,gsantovena/mesos,asamerh4/mesos,kaysoky/mesos,dforsyth/mesos,gsantovena/mesos,chhsia0/mesos,zmalik/mesos,neilconway/mesos,gsantovena/mesos,jpeach/mesos,chhsia0/mesos,asamerh4/mesos,asamerh4/mesos,andschwa/mesos,andschwa/mesos,verizonlabs/mesos,verizonlabs/mesos,kaysoky/mesos,Gilbert88/mesos,verizonlabs/mesos,dforsyth/mesos,dforsyth/mesos,abudnik/mesos,zmalik/mesos,Gilbert88/mesos,verizonlabs/mesos,dforsyth/mesos,zmalik/mesos,kaysoky/mesos,chhsia0/mesos,andschwa/mesos,verizonlabs/mesos,jpeach/mesos,reneploetz/mesos,neilconway/mesos,abudnik/mesos,dforsyth/mesos,andschwa/mesos,abudnik/mesos,kaysoky/mesos,jpeach/mesos,chhsia0/mesos,verizonlabs/mesos,reneploetz/mesos