Merge pull request #953 from BranchMetrics/SDK-594-tune-check-only-works-on-first-install

SDK-594 fix tune data check only works once

Author: echo-branch

Branch-SDK/Branch-SDK/BNCTuneUtility.m

@@ -12,7 +12,7 @@ @implementation BNCTuneUtility
 
 // INTENG-7695 Tune data indicates an app upgrading from Tune SDK to Branch SDK
 + (BOOL)isTuneDataPresent {
-    __block BOOL isPresent = NO;
+    static BOOL isPresent = NO;
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{
         NSString *tuneMatIdKey = @"_TUNE_mat_id";