Drop Ubuntu 13.10, 14.04 builds
Drop Ubuntu 13.10, 14.04 builds

These don't support regex_replace.

http://hydra.nixos.org/build/39363999
http://hydra.nixos.org/build/39363981

shlevy/nix,zimbatm/nix,rycee/nix,dezgeg/nix,shlevy/nix,peti/nix,ehmry/nix,shlevy/nix,rycee/nix,layus/nix,bennofs/nix,vcunat/nix,dtzWill/nix,dtzWill/nix,ysangkok/nix,layus/nix,dezgeg/nix,pikajude/nix,layus/nix,bennofs/nix,peti/nix,vcunat/nix,ehmry/nix,ehmry/nix,shlevy/nix,bennofs/nix,NixOS/nix,dtzWill/nix,vcunat/nix,vcunat/nix,rycee/nix,dezgeg/nix,zimbatm/nix,zimbatm/nix,dezgeg/nix,shlevy/nix,dtzWill/nix,ehmry/nix,pikajude/nix,dtzWill/nix,bennofs/nix,rycee/nix,NixOS/nix,ysangkok/nix,NixOS/nix,rycee/nix,peti/nix,layus/nix,NixOS/nix,pikajude/nix,peti/nix,ehmry/nix,zimbatm/nix,ysangkok/nix,ehmry/nix,dezgeg/nix,layus/nix,NixOS/nix,peti/nix