[git-llvm] Don't attempt to propget files that don't exist yet in SVN

svn propget will fail halfway through, and the patch will fail to apply.

llvm-svn: 303359
diff --git a/llvm/utils/git-svn/git-llvm b/llvm/utils/git-svn/git-llvm
index 55d3129..9309889 100755
--- a/llvm/utils/git-svn/git-llvm
+++ b/llvm/utils/git-svn/git-llvm
@@ -202,6 +202,8 @@
     files = git('diff-tree', '--no-commit-id', '--name-only', '-r', rev, '--',
                 sr).split('\n')
     files = [f.split('/', 1)[1] for f in files]
+    # Skip files that don't exist in SVN yet.
+    files = [f for f in files if os.path.exists(os.path.join(svn_sr_path, f))]
     # Use ignore_errors because 'svn propget' prints errors if the file doesn't
     # have the named property. There doesn't seem to be a way to suppress that.
     eol_props = svn(svn_sr_path, 'propget', 'svn:eol-style', *files,