Remove usage of deprecated Throwables methods

The propagate and propagateIfPossible methods are deprecated in
Guava 20. Replace them with the recommended alternatives.

Change-Id: I8aacba415a15655850c9d2e7ba8bd207db930460
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java b/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
index 06cbe33..b20f8eb 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/Destination.java
@@ -220,7 +220,8 @@
       stateLog.error(String.format("source project %s not available", project),
           err, states);
     } catch (Exception e) {
-      throw Throwables.propagate(e);
+      Throwables.throwIfUnchecked(e);
+      throw new RuntimeException(e);
     }
     return false;
   }
@@ -238,7 +239,7 @@
       stateLog.error(String.format("source project %s not available", project),
           err, states);
     } catch (Exception e) {
-      Throwables.propagateIfPossible(e);
+      Throwables.throwIfUnchecked(e);
       throw new RuntimeException(e);
     }
     return false;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index a251832..99b28e3 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -286,7 +286,7 @@
         }
       }).call();
     } catch (Exception e) {
-      Throwables.propagateIfPossible(e);
+      Throwables.throwIfUnchecked(e);
       throw new RuntimeException(e);
     } finally {
       statesCleanUp();