Remove external/rust/crates/libz-sys/.gitmodules.
git doesn't support submodules in external directory.
Didn't remove the following directories because they have files.
src/zlib and src/zlib-ng
Bug: 152899985
Test: Presubmit-Verify
Change-Id: I3973aeec8f7e19c3bbe1746ce50fff72c333da1e
diff --git a/.gitmodules b/.gitmodules
deleted file mode 100644
index 16e5824..0000000
--- a/.gitmodules
+++ /dev/null
@@ -1,6 +0,0 @@
-[submodule "src/zlib"]
- path = src/zlib
- url = https://github.com/madler/zlib
-[submodule "src/zlib-ng"]
- path = src/zlib-ng
- url = https://github.com/zlib-ng/zlib-ng
