Revert to Go 1.9.6 for Android

- Due to possible stability issues.

MobileLibrary/Android/Dockerfile

@@ -19,7 +19,7 @@ RUN apt-get update -y && apt-get install -y --no-install-recommends \
   && rm -rf /var/lib/apt/lists/*
 
 # Install Go.
-ENV GOVERSION=go1.11.1 GOROOT=/usr/local/go GOPATH=/go PATH=$PATH:/usr/local/go/bin:/go/bin CGO_ENABLED=1
+ENV GOVERSION=go1.9.6 GOROOT=/usr/local/go GOPATH=/go PATH=$PATH:/usr/local/go/bin:/go/bin CGO_ENABLED=1
 
 RUN curl -L https://storage.googleapis.com/golang/$GOVERSION.linux-amd64.tar.gz -o /tmp/go.tar.gz \
   && tar -C /usr/local -xzf /tmp/go.tar.gz \