handle potential URLError from sending shutdown, set self.process to None after it's already been quit
handle potential URLError from sending shutdown, set self.process to None after it's already been quit

Fixes #1504

jsakamoto/selenium,SeleniumHQ/selenium,bayandin/selenium,davehunt/selenium,valfirst/selenium,5hawnknight/selenium,lmtierney/selenium,SeleniumHQ/selenium,sag-enorman/selenium,asolntsev/selenium,DrMarcII/selenium,xmhubj/selenium,jabbrwcky/selenium,sag-enorman/selenium,bayandin/selenium,lukeis/selenium,joshmgrant/selenium,tbeadle/selenium,uchida/selenium,lmtierney/selenium,joshmgrant/selenium,carlosroh/selenium,mojwang/selenium,twalpole/selenium,dibagga/selenium,bayandin/selenium,jabbrwcky/selenium,dibagga/selenium,gurayinan/selenium,sankha93/selenium,TikhomirovSergey/selenium,p0deje/selenium,p0deje/selenium,kalyanjvn1/selenium,krmahadevan/selenium,alb-i986/selenium,kalyanjvn1/selenium,Tom-Trumper/selenium,lmtierney/selenium,jsakamoto/selenium,chrisblock/selenium,chrisblock/selenium,Dude-X/selenium,SeleniumHQ/selenium,mach6/selenium,oddui/selenium,xsyntrex/selenium,sag-enorman/selenium,titusfortner/selenium,gurayinan/selenium,uchida/selenium,bayandin/selenium,TikhomirovSergey/selenium,GorK-ChO/selenium,joshbruning/selenium,gurayinan/selenium,krmahadevan/selenium,Dude-X/selenium,valfirst/selenium,DrMarcII/selenium,bayandin/selenium,kalyanjvn1/selenium,krmahadevan/selenium,joshbruning/selenium,twalpole/selenium,joshmgrant/selenium,joshuaduffy/selenium,oddui/selenium,titusfortner/selenium,HtmlUnit/selenium,DrMarcII/selenium,dibagga/selenium,davehunt/selenium,juangj/selenium,mach6/selenium,mach6/selenium,joshuaduffy/selenium,SeleniumHQ/selenium,chrisblock/selenium,titusfortner/selenium,valfirst/selenium,oddui/selenium,sankha93/selenium,asolntsev/selenium,SeleniumHQ/selenium,p0deje/selenium,davehunt/selenium,tbeadle/selenium,twalpole/selenium,titusfortner/selenium,joshbruning/selenium,sag-enorman/selenium,uchida/selenium,asashour/selenium,lmtierney/selenium,bayandin/selenium,p0deje/selenium,asolntsev/selenium,Dude-X/selenium,Tom-Trumper/selenium,xmhubj/selenium,carlosroh/selenium,Ardesco/selenium,sankha93/selenium,jabbrwcky/selenium,tbeadle/selenium,xmhubj/selenium,juangj/selenium,joshmgrant/selenium,gurayinan/selenium,markodolancic/selenium,jsakamoto/selenium,alb-i986/selenium,jabbrwcky/selenium,chrisblock/selenium,joshbruning/selenium,chrisblock/selenium,Tom-Trumper/selenium,GorK-ChO/selenium,dibagga/selenium,chrisblock/selenium,p0deje/selenium,joshuaduffy/selenium,uchida/selenium,mojwang/selenium,DrMarcII/selenium,lukeis/selenium,joshbruning/selenium,jabbrwcky/selenium,DrMarcII/selenium,5hawnknight/selenium,lukeis/selenium,HtmlUnit/selenium,krmahadevan/selenium,asolntsev/selenium,sankha93/selenium,valfirst/selenium,5hawnknight/selenium,Jarob22/selenium,tbeadle/selenium,TikhomirovSergey/selenium,TikhomirovSergey/selenium,xsyntrex/selenium,gurayinan/selenium,lmtierney/selenium,asolntsev/selenium,lukeis/selenium,twalpole/selenium,TikhomirovSergey/selenium,alb-i986/selenium,xsyntrex/selenium,joshbruning/selenium,lukeis/selenium,GorK-ChO/selenium,mach6/selenium,HtmlUnit/selenium,bayandin/selenium,markodolancic/selenium,Jarob22/selenium,markodolancic/selenium,Herst/selenium,gurayinan/selenium,HtmlUnit/selenium,mojwang/selenium,tbeadle/selenium,lmtierney/selenium,xsyntrex/selenium,davehunt/selenium,lmtierney/selenium,xmhubj/selenium,titusfortner/selenium,Herst/selenium,chrisblock/selenium,Tom-Trumper/selenium,joshmgrant/selenium,tbeadle/selenium,carlosroh/selenium,sag-enorman/selenium,asolntsev/selenium,alb-i986/selenium,jsakamoto/selenium,krmahadevan/selenium,Ardesco/selenium,juangj/selenium,markodolancic/selenium,Tom-Trumper/selenium,carlosroh/selenium,asolntsev/selenium,joshbruning/selenium,uchida/selenium,HtmlUnit/selenium,titusfortner/selenium,carlosroh/selenium,mach6/selenium,joshbruning/selenium,p0deje/selenium,xsyntrex/selenium,xsyntrex/selenium,Dude-X/selenium,krmahadevan/selenium,juangj/selenium,Dude-X/selenium,markodolancic/selenium,bayandin/selenium,SeleniumHQ/selenium,Herst/selenium,asashour/selenium,SeleniumHQ/selenium,HtmlUnit/selenium,oddui/selenium,DrMarcII/selenium,lmtierney/selenium,alb-i986/selenium,Jarob22/selenium,SeleniumHQ/selenium,Herst/selenium,Ardesco/selenium,p0deje/selenium,xsyntrex/selenium,xmhubj/selenium,davehunt/selenium,sankha93/selenium,dibagga/selenium,uchida/selenium,valfirst/selenium,p0deje/selenium,oddui/selenium,davehunt/selenium,valfirst/selenium,titusfortner/selenium,Ardesco/selenium,mojwang/selenium,mach6/selenium,DrMarcII/selenium,juangj/selenium,uchida/selenium,oddui/selenium,alb-i986/selenium,valfirst/selenium,mojwang/selenium,oddui/selenium,xsyntrex/selenium,jabbrwcky/selenium,twalpole/selenium,twalpole/selenium,asolntsev/selenium,xmhubj/selenium,Tom-Trumper/selenium,tbeadle/selenium,Tom-Trumper/selenium,5hawnknight/selenium,lukeis/selenium,TikhomirovSergey/selenium,kalyanjvn1/selenium,juangj/selenium,twalpole/selenium,titusfortner/selenium,kalyanjvn1/selenium,gurayinan/selenium,joshuaduffy/selenium,tbeadle/selenium,xmhubj/selenium,joshmgrant/selenium,markodolancic/selenium,xmhubj/selenium,joshuaduffy/selenium,Dude-X/selenium,titusfortner/selenium,carlosroh/selenium,davehunt/selenium,mach6/selenium,mach6/selenium,asashour/selenium,Jarob22/selenium,alb-i986/selenium,Jarob22/selenium,sag-enorman/selenium,sankha93/selenium,Tom-Trumper/selenium,HtmlUnit/selenium,lukeis/selenium,Jarob22/selenium,Ardesco/selenium,joshmgrant/selenium,oddui/selenium,jsakamoto/selenium,xsyntrex/selenium,kalyanjvn1/selenium,uchida/selenium,joshuaduffy/selenium,joshuaduffy/selenium,Herst/selenium,sag-enorman/selenium,asashour/selenium,kalyanjvn1/selenium,valfirst/selenium,carlosroh/selenium,joshmgrant/selenium,GorK-ChO/selenium,juangj/selenium,markodolancic/selenium,Dude-X/selenium,5hawnknight/selenium,asashour/selenium,oddui/selenium,carlosroh/selenium,TikhomirovSergey/selenium,5hawnknight/selenium,joshbruning/selenium,Tom-Trumper/selenium,jabbrwcky/selenium,juangj/selenium,Ardesco/selenium,Ardesco/selenium,valfirst/selenium,chrisblock/selenium,sankha93/selenium,uchida/selenium,Jarob22/selenium,Jarob22/selenium,DrMarcII/selenium,kalyanjvn1/selenium,dibagga/selenium,jabbrwcky/selenium,GorK-ChO/selenium,lukeis/selenium,TikhomirovSergey/selenium,valfirst/selenium,Ardesco/selenium,mojwang/selenium,davehunt/selenium,GorK-ChO/selenium,sankha93/selenium,juangj/selenium,GorK-ChO/selenium,carlosroh/selenium,krmahadevan/selenium,sag-enorman/selenium,asashour/selenium,kalyanjvn1/selenium,tbeadle/selenium,jsakamoto/selenium,joshuaduffy/selenium,titusfortner/selenium,markodolancic/selenium,joshmgrant/selenium,jsakamoto/selenium,joshmgrant/selenium,xmhubj/selenium,joshuaduffy/selenium,5hawnknight/selenium,joshmgrant/selenium,lukeis/selenium,dibagga/selenium,jsakamoto/selenium,sag-enorman/selenium,Herst/selenium,mach6/selenium,Jarob22/selenium,5hawnknight/selenium,Herst/selenium,mojwang/selenium,SeleniumHQ/selenium,krmahadevan/selenium,gurayinan/selenium,bayandin/selenium,krmahadevan/selenium,Ardesco/selenium,DrMarcII/selenium,asashour/selenium,HtmlUnit/selenium,jabbrwcky/selenium,SeleniumHQ/selenium,Herst/selenium,asolntsev/selenium,GorK-ChO/selenium,p0deje/selenium,HtmlUnit/selenium,5hawnknight/selenium,gurayinan/selenium,mojwang/selenium,twalpole/selenium,mojwang/selenium,davehunt/selenium,Dude-X/selenium,chrisblock/selenium,dibagga/selenium,alb-i986/selenium,lmtierney/selenium,asashour/selenium,sankha93/selenium,asashour/selenium,jsakamoto/selenium,Herst/selenium,GorK-ChO/selenium,Dude-X/selenium,HtmlUnit/selenium,SeleniumHQ/selenium,twalpole/selenium,titusfortner/selenium,valfirst/selenium,TikhomirovSergey/selenium,markodolancic/selenium,dibagga/selenium,alb-i986/selenium