fix top.py on freebsd
fix top.py on freebsd

djhaskin987/psutil,vmolsa/psutil,skyshe/psutil,djhaskin987/psutil,end18/psutil,end18/psutil,creativewild/psutil,AlanZatarain/psutil,marmolu/psutil,vmolsa/psutil,chjwang/psutil,shiva21/psutil,kiranvizru/psutil,creativewild/psutil,anfedorov/psutil,google-code-export/psutil,nmani1905/psutil,Alwnikrotikz/psutil,peter-hst/psutil,zhengzheng/psutil,stupidcache/psutil,tigerneil/psutil,skyshe/psutil,vmolsa/psutil,google-code-export/psutil,AlanZatarain/psutil,Alwnikrotikz/psutil,end18/psutil,jucapj/psutil,jucapj/psutil,nmani1905/psutil,tigerneil/psutil,tigerneil/psutil,PFZheng/psutil,vmolsa/psutil,djhaskin987/psutil,djhaskin987/psutil,kiranvizru/psutil,tigerneil/psutil,peter-hst/psutil,huson2012/psutil,google-code-export/psutil,skyshe/psutil,huson2012/psutil,end18/psutil,skyshe/psutil,stupidcache/psutil,creativewild/psutil,google-code-export/psutil,kiranvizru/psutil,chjwang/psutil,huson2012/psutil,zhengzheng/psutil,stupidcache/psutil,marmolu/psutil,anfedorov/psutil,kiranvizru/psutil,shiva21/psutil,PFZheng/psutil