mdNavBar : wrong theme used

[melkhor14]

Actual Behavior:

• What is the issue? When a theme is defined via md-theme, the md-nav-ink-bar for the md-nav-bar element does not use the given theme, but the default one
• What is the expected behavior? The md-nav-ink-bar element should use the accent color of the theme

CodePen (or steps to reproduce the issue): *

• http://codepen.io/pyy/pen/QExbrK
• Here, the md-nav-ink-bar should be orange instead of the default pink

Angular Versions: *

• Angular Version: Any
• Angular Material Version: 1.1.0-rc.5