Remove .gitattributes file that tries to configure git-lfs

We don't support git-lfs in the Android tree, and this is causing `repo sync` to fail for users that do not have git-lfs installed.

Bug: 157703216
Test: treehugger
Change-Id: I6ed4ca1ba8910b6d8cc1c18bebbb1a67dc810455
diff --git a/.gitattributes b/.gitattributes
deleted file mode 100644
index 5299c47..0000000
--- a/.gitattributes
+++ /dev/null
@@ -1 +0,0 @@
-*.7z filter=lfs diff=lfs merge=lfs -text