Make generated Bazel match canonical format.

This should make buildifier[1] happy with the generated files.

[1] https://github.com/bazelbuild/buildtools

Change-Id: Ida6ba5a369d2564fc7b77ad8d8705183167a3615
Reviewed-on: https://boringssl-review.googlesource.com/18525
Reviewed-by: David Benjamin <davidben@google.com>

util/generate_build_files.py

@@ -229,7 +229,7 @@ class Bazel(object):
           continue
         out.write('    "%s",\n' % PathOf(filename))
 
-      out.write(']\n\n')
+      out.write(']\n')
 
       self.PrintVariableSection(out, 'crypto_test_sources',
                                 files['crypto_test'])