Use CentOS 6 instead of 7 for rhel-x64 RID

bording · bording · commit bd47a62bc93c · 2018-11-03T11:41:42.000-04:00
diff --git a/Dockerfile.rhel-x64 b/Dockerfile.rhel-x64
@@ -1,4 +1,4 @@
-FROM centos:7
+FROM centos:6
 WORKDIR /nativebinaries
 COPY . /nativebinaries/
 
