Remove superfluous min calls in RenderBlock::computeOverflow.

They are contained in an "if" statement that ensures that textIndent < 0
and so the min will never be 0.

BUG=

Review URL: https://chromiumcodereview.appspot.com/22645007

git-svn-id: svn://svn.chromium.org/blink/trunk@155876 bbb929c8-8fbe-4397-9dbb-9b2b20218538