Fix groovy typo in #20406

Author: RussKeldorph

netci.groovy

@@ -2392,7 +2392,7 @@ def static calculateBuildCommands(def newJob, def scenario, def branch, def isPR
                         buildCommands += "ROOTFS_DIR=/opt/arm64-xenial-rootfs ./build.sh verbose ${lowerConfiguration} ${architecture} cross clang3.8"
 
                         // HACK -- Arm64 does not have corefx jobs yet.
-                        buildCommands += "git clone -b {branch} https://github.com/dotnet/corefx fx"
+                        buildCommands += "git clone -b ${branch} https://github.com/dotnet/corefx fx"
                         buildCommands += "ROOTFS_DIR=/opt/arm64-xenial-rootfs-corefx ./fx/build-native.sh -release -buildArch=arm64 -- verbose cross clang3.8"
                         buildCommands += "mkdir ./bin/Product/Linux.arm64.${configuration}/corefxNative"
                         buildCommands += "cp fx/bin/Linux.arm64.Release/native/* ./bin/Product/Linux.arm64.${configuration}/corefxNative"