Update glorot_uniform_initializer to match other Initializers

This fix tries to address the issue raised in 19910 where
the signature of glorot_uniform_initializer does not match
other Initializers (e.g., random_uniform_initializer).

This fix update the glorot_uniform_initializer so that
it matches the signature in a similiar way as other
Initializers.

This fix fixes 19910.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>