text: Title: Unable to chain find_by_css().find_by_text() with 0.9.0
  Body: https://github.com/cobrateam/splinter/issues/426 seems to have resurfaced in 0.9.0.
  
  With 0.8.0, `browser.find_by_css(".onboarding-modal").find_by_text("Slack")` finds one element on my site, but 0.9.0 returns none.
  
  I think https://github.com/cobrateam/splinter/commit/1cfd05086a5ccb1c3297072e2bc0e713e71b2156 is the commit that changed this behavior.
  
  I can try to find a reproduceable example on a public site if necessary.