Reordered function definitions in master actor HTTP handlers.
Reordered function definitions in master actor HTTP handlers.

This change performs the following function definition reordering:

\- It groups pre v1 API/v1 Master API handlers nearby for better
readability. There were already some functions already doing this.
\- For some handlers that use a helper function, it defines them
\_before\_ the HELP string variable. This means that now the
HELP strings immediatly precede the handler implementation
which is more intuitive to the reader.

Review: https://reviews.apache.org/r/49000/

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