Fixed the commit message hook to wrap the variables in quotes.
Fixed the commit message hook to wrap the variables in quotes.

Some symbols, e.g., '*' can be expanded by the shell altering the
original line and hence leading to false positives.

Review: https://reviews.apache.org/r/45984/

abudnik/mesos,asamerh4/mesos,chhsia0/mesos,dforsyth/mesos,kaysoky/mesos,Gilbert88/mesos,reneploetz/mesos,verizonlabs/mesos,craimbert/mesos,craimbert/mesos,craimbert/mesos,abudnik/mesos,chhsia0/mesos,andschwa/mesos,kaysoky/mesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,gsantovena/mesos,jpeach/mesos,yuquanshan/customizedMesos,andschwa/mesos,reneploetz/mesos,yuquanshan/customizedMesos,jpeach/mesos,chhsia0/mesos,jpeach/mesos,Gilbert88/mesos,abudnik/mesos,abudnik/mesos,jpeach/mesos,zmalik/mesos,abudnik/mesos,reneploetz/mesos,verizonlabs/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,verizonlabs/mesos,chhsia0/mesos,Gilbert88/mesos,asamerh4/mesos,asamerh4/mesos,neilconway/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,craimbert/mesos,reneploetz/mesos,andschwa/mesos,neilconway/mesos,Aman-Jain-14/customizedMesos,reneploetz/mesos,Gilbert88/mesos,Aman-Jain-14/customizedMesos,zmalik/mesos,Aman-Jain-14/customizedMesos,neilconway/mesos,asamerh4/mesos,Gilbert88/mesos,yuquanshan/customizedMesos,yuquanshan/customizedMesos,dforsyth/mesos,neilconway/mesos,andschwa/mesos,verizonlabs/mesos,dforsyth/mesos,reneploetz/mesos,andschwa/mesos,neilconway/mesos,gsantovena/mesos,yuquanshan/customizedMesos,asamerh4/mesos,abudnik/mesos,chhsia0/mesos,dforsyth/mesos,andschwa/mesos,andschwa/mesos,gsantovena/mesos,jpeach/mesos,zmalik/mesos,reneploetz/mesos,yuquanshan/customizedMesos,gsantovena/mesos,kaysoky/mesos,zmalik/mesos,neilconway/mesos,gsantovena/mesos,kaysoky/mesos,zmalik/mesos,Gilbert88/mesos,verizonlabs/mesos,chhsia0/mesos,yuquanshan/customizedMesos,zmalik/mesos,craimbert/mesos,Gilbert88/mesos,asamerh4/mesos,dforsyth/mesos,dforsyth/mesos,jpeach/mesos,zmalik/mesos,asamerh4/mesos,neilconway/mesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,verizonlabs/mesos,gsantovena/mesos,verizonlabs/mesos,gsantovena/mesos,craimbert/mesos,dforsyth/mesos,abudnik/mesos,kaysoky/mesos,chhsia0/mesos