url: delete href cache on all setter code paths

PR-URL: https://github.com/iojs/io.js/pull/1589
Fixes: https://github.com/iojs/io.js/issues/1588
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

lib/url.js

@@ -1041,8 +1041,8 @@ Object.defineProperty(Url.prototype, 'host', {
         this._port = -1;
         this._hostname = this._host = encodeURIComponent(host);
       }
-      this._href = '';
     }
+    this._href = '';
   },
   enumerable: true,
   configurable: true
@@ -1068,9 +1068,8 @@ Object.defineProperty(Url.prototype, 'hostname', {
         this._host = hostname + ':' + this._port;
       else
         this._host = hostname;
-
-      this._href = '';
     }
+    this._href = '';
   },
   enumerable: true,
   configurable: true
@@ -1089,8 +1088,8 @@ Object.defineProperty(Url.prototype, 'hash', {
         hash = '#' + hash;
       }
       this._hash = hash;
-      this._href = '';
     }
+    this._href = '';
   },
   enumerable: true,
   configurable: true
@@ -1114,8 +1113,8 @@ Object.defineProperty(Url.prototype, 'search', {
       if (this._parsesQueryStrings) {
         this.query = querystring.parse(search.slice(1));
       }
-      this._href = '';
     }
+    this._href = '';
   },
   enumerable: true,
   configurable: true
@@ -1138,8 +1137,8 @@ Object.defineProperty(Url.prototype, 'pathname', {
       }
 
       this._pathname = pathname;
-      this._href = '';
     }
+    this._href = '';
   },
   enumerable: true,
   configurable: true