Fix tests that compare Resources::count() with signed integers.
Fix tests that compare Resources::count() with signed integers.

Resources::count() returns size_t, so the check needs to be for
unsigned integers.

Review: https://reviews.apache.org/r/50676/

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