[GLUTEN-7035][VL] Use first line of ls-remote's output as build's t…

…arget commit (apache#7036)

Closes apache#7035

ep/build-velox/src/get_velox.sh

@@ -151,7 +151,7 @@ fi
 VELOX_SOURCE_DIR="${VELOX_HOME}"
 
 # checkout code
-TARGET_BUILD_COMMIT="$(git ls-remote $VELOX_REPO $VELOX_BRANCH | awk '{print $1;}')"
+TARGET_BUILD_COMMIT="$(git ls-remote $VELOX_REPO $VELOX_BRANCH | awk '{print $1;}' | head -n 1)"
 if [ -d $VELOX_SOURCE_DIR ]; then
   echo "Velox source folder $VELOX_SOURCE_DIR already exists..."
   cd $VELOX_SOURCE_DIR