Don't unset gFCSafeToUse when it's still safe to use.

BUG=skia:
R=bungeman@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/240513003

git-svn-id: http://skia.googlecode.com/svn/trunk@14232 2bbb7eff-a529-9590-31e7-b0007b416f81

src/fonts/SkFontMgr_fontconfig.cpp

@@ -38,8 +38,8 @@ struct FCLocker {
     }
 
     ~FCLocker() {
-        gFCSafeToUse = false;
         if (fUnlock) {
+            gFCSafeToUse = false;
             gFCMutex.release();
         }
     }