Revert "Raise the default bandwidth estimate"

This reverts commit a4d2aca.

Author: joeyparrish

lib/util/player_configuration.js

@@ -35,9 +35,10 @@ goog.require('shaka.util.ConfigUtils');
 shaka.util.PlayerConfiguration = class {
   /** @return {shaka.extern.PlayerConfiguration} */
   static createDefault() {
-    // This is a relatively safe default in the absence of clues from the
-    // browser.  For slower connections, the default estimate may be too high.
-    let bandwidthEstimate = 1e6; // 1Mbps
+    // This is a relatively safe default, since 3G cell connections
+    // are faster than this.  For slower connections, such as 2G,
+    // the default estimate may be too high.
+    let bandwidthEstimate = 500e3; // 500kbps
 
     let abrMaxHeight = Infinity;