do_cmake.sh: do not perform 'git submodule update' if building from tarball

Signed-off-by: Vladimir Bashkirtsev <vladimir@bashkirtsev.com>

diff --git a/do_cmake.sh b/do_cmake.sh
index 345986d630c7c5f0a6c0d3bc0c473c7be260c710..4cb07c106b6c9478be72a40010eebc99b23ebf53 100755 (executable)
--- a/do_cmake.sh
+++ b/do_cmake.sh
@@ -1,7 +1,9 @@
 #!/usr/bin/env bash
 set -ex
 
-git submodule update --init --recursive
+if [ -d .git ]; then
+    git submodule update --init --recursive
+fi
 
 : ${BUILD_DIR:=build}
 : ${CEPH_GIT_DIR:=..}