fix(autocomplete): fixes positioning of progress bar

Closes #3115

Author: Robert Messerle

src/components/autocomplete/autocomplete.scss

@@ -68,7 +68,7 @@ md-autocomplete {
     position: relative;
     overflow: visible;
     height: 40px;
-    md-progress-linear {
+    md-progress-linear[md-mode=indeterminate] {
       position: absolute;
       bottom: 0; left: 0; width: 100%;
       height: 3px;