Change login button class to blend in better with custom header backgrounds

src/main/java/com/gitblit/wicket/pages/RootPage.html

@@ -40,7 +40,7 @@
 				<span class="form-search">
 					<input wicket:id="username" class="input-small" type="text" />
 					<input wicket:id="password" class="input-small" type="password" />
-					<button class="btn btn-primary" type="submit"><wicket:message key="gb.login"></wicket:message></button>
+					<button class="btn" type="submit"><wicket:message key="gb.login"></wicket:message></button>
 				</span>
 			</form>
 		</li>