Fix zero-length field name error in python2.6
Fix zero-length field name error in python2.6

markshao/pytest,davidszotten/pytest,hackebrot/pytest,RonnyPfannschmidt/pytest,ddboline/pytest,flub/pytest,The-Compiler/pytest,rmfitzpatrick/pytest,tareqalayan/pytest,etataurov/pytest,tomviner/pytest,skylarjhdownes/pytest,pytest-dev/pytest,txomon/pytest,pfctdayelise/pytest,tomviner/pytest,hpk42/pytest,hpk42/pytest,The-Compiler/pytest,alfredodeza/pytest,eli-b/pytest,malinoff/pytest,tgoodlet/pytest,nicoddemus/pytest,nicoddemus/pytest,Akasurde/pytest,jaraco/pytest,MichaelAquilina/pytest,vmalloc/dessert