Clean `build`, not `builds`, directory.
Clean `build`, not `builds`, directory.

fix bug 1062710

rhelmer/socorro,mozilla/socorro,KaiRo-at/socorro,AdrianGaudebert/socorro,spthaolt/socorro,twobraids/socorro,m8ttyB/socorro,lonnen/socorro,cliqz/socorro,AdrianGaudebert/socorro,KaiRo-at/socorro,cliqz/socorro,spthaolt/socorro,spthaolt/socorro,Serg09/socorro,Tchanders/socorro,Tchanders/socorro,yglazko/socorro,Tchanders/socorro,adngdb/socorro,Tayamarn/socorro,mozilla/socorro,pcabido/socorro,linearregression/socorro,twobraids/socorro,rhelmer/socorro,m8ttyB/socorro,lonnen/socorro,mozilla/socorro,luser/socorro,luser/socorro,Tayamarn/socorro,cliqz/socorro,spthaolt/socorro,rhelmer/socorro,linearregression/socorro,rhelmer/socorro,rhelmer/socorro,Serg09/socorro,Tchanders/socorro,Tchanders/socorro,luser/socorro,linearregression/socorro,linearregression/socorro,cliqz/socorro,yglazko/socorro,twobraids/socorro,Tayamarn/socorro,adngdb/socorro,lonnen/socorro,pcabido/socorro,Serg09/socorro,m8ttyB/socorro,AdrianGaudebert/socorro,AdrianGaudebert/socorro,adngdb/socorro,KaiRo-at/socorro,Tayamarn/socorro,Serg09/socorro,spthaolt/socorro,pcabido/socorro,KaiRo-at/socorro,Tayamarn/socorro,adngdb/socorro,rhelmer/socorro,m8ttyB/socorro,yglazko/socorro,m8ttyB/socorro,m8ttyB/socorro,linearregression/socorro,cliqz/socorro,KaiRo-at/socorro,lonnen/socorro,pcabido/socorro,KaiRo-at/socorro,pcabido/socorro,linearregression/socorro,twobraids/socorro,yglazko/socorro,mozilla/socorro,Tayamarn/socorro,AdrianGaudebert/socorro,AdrianGaudebert/socorro,pcabido/socorro,yglazko/socorro,mozilla/socorro,mozilla/socorro,twobraids/socorro,yglazko/socorro,luser/socorro,luser/socorro,spthaolt/socorro,Serg09/socorro,cliqz/socorro,luser/socorro,Tchanders/socorro,adngdb/socorro,twobraids/socorro,adngdb/socorro,Serg09/socorro