Fix mdpi version of abc_textfield_default_mtrl_alpha.9.png

abc_textfield_default_mtrl_alpha.9.png had a mistakenly added
transparent row of pixels. This change clear those pixels to be
fully transparent.

Bug: 29395519
Change-Id: I2d5d45c7d0c79a291bbdb7e09c5268adcccd8f0e
1 file changed