Remove deprecated methods with Guava 20 release

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=137849843

javatests/google/registry/server/UrlChecker.java

@@ -45,7 +45,8 @@ final class UrlChecker {
         }
       }, timeoutMs, TimeUnit.MILLISECONDS, true);
     } catch (Exception e) {
-      throw Throwables.propagate(e);
+      Throwables.throwIfUnchecked(e);
+      throw new RuntimeException(e);
     }
   }