Include all potential build targets when cleaning, so scons will remove all targets.
Include all potential build targets when cleaning, so scons will
remove all targets.

* SConstruct:
  (): reset the Default when cleaning to include all targets

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