Pipe bazel() note text to stderr.

This allows subshell-ing bazel, e.g. bazel build $(bazel query //...)

Test: . build/envsetup.sh; bazel build $(bazel query <expression>)
Change-Id: If28b63769032b61e150422cb5b9b4e55c14cd13d
diff --git a/envsetup.sh b/envsetup.sh
index a2d5d1d..8fa608b 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -330,8 +330,8 @@
     fi
 
     if which bazel &>/dev/null; then
-        echo "NOTE: bazel() function sourced from envsetup.sh is being used instead of $(which bazel)"
-        echo
+        >&2 echo "NOTE: bazel() function sourced from envsetup.sh is being used instead of $(which bazel)"
+        >&2 echo
     fi
 
     "$T/tools/bazel" "$@"