Fix/duplicated async method (#1560)

* Removed another one duplicated async method

MJRefresh.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
     s.name         = 'MJRefresh'
-    s.version      = '3.7.4'
+    s.version      = '3.7.5'
     s.summary      = 'An easy way to use pull-to-refresh'
     s.homepage     = 'https://github.com/CoderMJLee/MJRefresh'
     s.license      = 'MIT'

MJRefresh/Base/MJRefreshComponent.m

@@ -237,17 +237,15 @@ - (void)setPullingPercent:(CGFloat)pullingPercent
 #pragma mark - 内部方法
 - (void)executeRefreshingCallback
 {
-    MJRefreshDispatchAsyncOnMainQueue({
-        if (self.refreshingBlock) {
-            self.refreshingBlock();
-        }
-        if ([self.refreshingTarget respondsToSelector:self.refreshingAction]) {
-            MJRefreshMsgSend(MJRefreshMsgTarget(self.refreshingTarget), self.refreshingAction, self);
-        }
-        if (self.beginRefreshingCompletionBlock) {
-            self.beginRefreshingCompletionBlock();
-        }
-    })
+    if (self.refreshingBlock) {
+        self.refreshingBlock();
+    }
+    if ([self.refreshingTarget respondsToSelector:self.refreshingAction]) {
+        MJRefreshMsgSend(MJRefreshMsgTarget(self.refreshingTarget), self.refreshingAction, self);
+    }
+    if (self.beginRefreshingCompletionBlock) {
+        self.beginRefreshingCompletionBlock();
+    }
 }
 
 #pragma mark - 刷新动画时间控制