Update src/java/azkaban/project/ProjectManager.java
Update src/java/azkaban/project/ProjectManager.java

When the uploaded file is not zip file, the fileType turns out to be null,
thus cause a nullpointer exception.
azkaban/azkaban,inoviaazkaban/azkaban,davidzchen/azkaban,mradamlacey/azkaban,linearregression/azkaban,reallocf/azkaban,logiclord/azkaban,evlstyle/azkaban,HappyRay/azkaban,jackrjli/azkaban,wangqiaoshi/azkaban,poporisil/azkaban3,nomorogbe/azkaban,kaneda/azkaban,cjyu/azkaban2,mariacioffi/azkaban,researchgate/azkaban,shixin198642/azkaban2,azkaban/azkaban,erwa/azkaban,researchgate/azkaban,Shopify/azkaban,reallocf/azkaban,reallocf/azkaban,reallocf/azkaban,weikang2002/azkaban,researchgate/azkaban,weikang2002/azkaban,wangqiaoshi/azkaban,poporisil/azkaban3,hluu/azkaban2,sunghyuk/azkaban,Shopify/azkaban,relateiq/azkaban,wangqiaoshi/azkaban,hluu/azkaban2,mradamlacey/azkaban,hluu/azkaban2,poporisil/azkaban3,chengren311/azkaban,sunghyuk/azkaban,cjyu/azkaban2,FelixGV/azkaban2,nomorogbe/azkaban,erwa/azkaban,relateiq/azkaban,johnyu0520/azkaban,johnyu0520/azkaban,HappyRay/azkaban,binhnv/azkaban,jackrjli/azkaban,jackrjli/azkaban,mariacioffi/azkaban,logiclord/azkaban,jackrjli/azkaban,nomorogbe/azkaban,FelixGV/azkaban2,evlstyle/azkaban,binhnv/azkaban,chengren311/azkaban,kaneda/azkaban,mradamlacey/azkaban,linearregression/azkaban,binhnv/azkaban,sunghyuk/azkaban,evlstyle/azkaban,cjyu/azkaban2,HappyRay/azkaban,azkaban/azkaban,chengren311/azkaban,mariacioffi/azkaban,logiclord/azkaban,sunghyuk/azkaban,erwa/azkaban,linearregression/azkaban,davidzchen/azkaban,FelixGV/azkaban2,shixin198642/azkaban2,mradamlacey/azkaban,inoviaazkaban/azkaban,johnyu0520/azkaban,backingwu/azkaban,HappyRay/azkaban,mradamlacey/azkaban,binhnv/azkaban,erwa/azkaban,jackrjli/azkaban,HappyRay/azkaban,researchgate/azkaban,azkaban/azkaban,poporisil/azkaban3,inoviaazkaban/azkaban,johnyu0520/azkaban,binhnv/azkaban,relateiq/azkaban,azkaban/azkaban,azkaban/azkaban,davidzchen/azkaban,poporisil/azkaban3,mariacioffi/azkaban,chengren311/azkaban,chengren311/azkaban,shixin198642/azkaban2,gradleupdate/azkaban2,relateiq/azkaban,evlstyle/azkaban,weikang2002/azkaban,davidzchen/azkaban,erwa/azkaban,logiclord/azkaban,mariacioffi/azkaban,sunghyuk/azkaban,backingwu/azkaban,reallocf/azkaban,backingwu/azkaban,kaneda/azkaban,HappyRay/azkaban,gradleupdate/azkaban2,gradleupdate/azkaban2,Shopify/azkaban