Fix URLs for flipping between otp/u2f

server/templates/login_otp.html

@@ -29,7 +29,7 @@
 
     {{if .AuthResponse.Has2FAMethod "u2f"}}
 <p>
-  <a href="{{.URLPrefix}}/login?2fa=u2f">
+  <a href="{{.URLPrefix}}/login/u2f">
     Use a hardware token instead.
   </a>
 </p>

server/templates/login_u2f.html

@@ -31,7 +31,7 @@
 
     {{if .AuthResponse.Has2FAMethod "otp"}}
 <p>
-  <a href="{{.URLPrefix}}/login?2fa=otp">
+  <a href="{{.URLPrefix}}/login/otp">
     Use a numeric one-time token instead.
   </a>
 </p>