Fix some issues with new Conduit method implementations

Summary: Ref T5655. A few of these were missed.

Test Plan:
Checked all other methods like this:

```
    foreach ($method_map as $k => $v) {
      $v = preg_replace('/ConduitAPIMethod$/', '', $v);
      $k = str_replace('.', '', $k);
      $v = strtolower($v);
      if ($k != $v) {
        echo "{$k} x {$v}!\n";
      }
    }
    echo "OK\n";
```

Reviewers: hach-que, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Maniphest Tasks: T5655

Differential Revision: https://secure.phabricator.com/D10049

src/applications/conduit/call/ConduitCall.php

@@ -172,7 +172,7 @@ final class ConduitCall {
     $method = ConduitAPIMethod::getConduitMethod($method_name);
 
     if (!$method) {
-      throw new ConduitMethodNotFoundException($method);
+      throw new ConduitMethodNotFoundException($method_name);
     }
 
     $application = $method->getApplication();

src/applications/conduit/method/ConduitAPIMethod.php

@@ -96,7 +96,6 @@ abstract class ConduitAPIMethod
     if ($method_map === null) {
       $methods = id(new PhutilSymbolLoader())
         ->setAncestorClass(__CLASS__)
-        ->setConcreteOnly(true)
         ->loadObjects();
 
       foreach ($methods as $method) {

src/applications/diffusion/conduit/DiffusionResolveRefsConduitAPIMethod.php

@@ -4,7 +4,7 @@ final class DiffusionResolveRefsConduitAPIMethod
   extends DiffusionQueryConduitAPIMethod {
 
   public function getAPIMethodName() {
-    return 'differential.resolverefsquery';
+    return 'diffusion.resolverefs';
   }
 
   public function getMethodDescription() {

src/applications/diffusion/conduit/DiffusionSearchQueryConduitAPIMethod.php

@@ -4,7 +4,7 @@ final class DiffusionSearchQueryConduitAPIMethod
   extends DiffusionQueryConduitAPIMethod {
 
   public function getAPIMethodName() {
-    return 'differential.searchquery';
+    return 'diffusion.searchquery';
   }
 
   public function getMethodDescription() {

src/applications/diffusion/conduit/DiffusionTagsQueryConduitAPIMethod.php

@@ -4,7 +4,7 @@ final class DiffusionTagsQueryConduitAPIMethod
   extends DiffusionQueryConduitAPIMethod {
 
   public function getAPIMethodName() {
-    return 'differential.tagsquery';
+    return 'diffusion.tagsquery';
   }
 
   public function getMethodDescription() {