Return default value of true from TextEditor.getAutoHeight

When we need to check for unassigned in the deprecated code path, we
can just read the instance variable directly to avoid getting the
deafult.

Signed-off-by: Antonio Scandurra <as-cii@github.com>

src/text-editor-component.coffee

@@ -57,7 +57,7 @@ class TextEditorComponent
       cursorBlinkResumeDelay: @cursorBlinkResumeDelay
       stoppedScrollingDelay: 200
       lineTopIndex: lineTopIndex
-      autoHeight: @editor.getAutoHeight() ? true
+      autoHeight: @editor.getAutoHeight()
 
     @presenter.onDidUpdateState(@requestUpdate)
 
@@ -759,7 +759,7 @@ class TextEditorComponent
     # auto-height in certain circumstances. This is legacy behavior that we
     # would rather not implement, but we can't remove it without risking
     # breakage currently.
-    unless @editor.getAutoHeight()?
+    unless @editor.autoHeight?
       {position, top, bottom} = getComputedStyle(@hostElement)
       hasExplicitTopAndBottom = (position is 'absolute' and top isnt 'auto' and bottom isnt 'auto')