Remove posix-ism. The 'if' statement does not have '!'
Remove posix-ism. The 'if' statement does not have '!'

* build/check.sh: rejigger 'if ! ...' statements

krime/serf,idomon/serf,TommyU/serf,TommyU/serf,Manouchehri/serf,liuzongquan/serf,liuzongquan/serf,blueszhangsh/serf,sworda/serf,sworda/serf,krime/serf,Manouchehri/serf,blueszhangsh/serf,krime/serf,sworda/serf,Manouchehri/serf,justinweb/serf,wzugang/serf,Manouchehri/serf,blueszhangsh/serf,wzugang/serf,muthusuba/serf,idomon/serf,justinweb/serf,muthusuba/serf,muthusuba/serf,TommyU/serf,TommyU/serf,wzugang/serf,muthusuba/serf,liuzongquan/serf,justinweb/serf,sworda/serf,blueszhangsh/serf,wzugang/serf,justinweb/serf,krime/serf,idomon/serf,liuzongquan/serf,idomon/serf