Remove empty line between copyright and build file docstring. (#1084)

This makes modifying it with buildozer easier. When the empty line is
present, Buildozer gets confused and adds loads() before the intended
doc string.

Author: rickeylev

python/BUILD.bazel

@@ -11,7 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 """This package contains two sets of rules:
 
     1) the "core" Python rules, which were historically bundled with Bazel and