Fix Gradle wrapper usage on Windows when building BWC (elastic/x-pack-elasticsearch#3509)
Fix Gradle wrapper usage on Windows when building BWC (elastic/x-pack-elasticsearch#3509)

Relates elastic/x-pack-elasticsearch#3502

Original commit: elastic/x-pack-elasticsearch@de69017a4f3591cb07f104212e5e2bacd6f877cf

gfyoung/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,robin13/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,HonzaKral/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,coding0011/elasticsearch,GlenRSmith/elasticsearch,robin13/elasticsearch,gfyoung/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,nknize/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,gfyoung/elasticsearch,nknize/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,nknize/elasticsearch