Update Guava to 19.0-rc1

Release 19 includes several bug fixes and API updates [1].

- Remove "unchecked" warning suppressions that are no longer
  necessary.

- Replace calls to deprecated Futures.transform() with new
  Futures.transformAsync().

- Use CharMatcher's static factory methods instead of constants
  that will later be deprecated.

[1] https://github.com/google/guava/wiki/Release19

Change-Id: I512ddc6ccf7ebaac0c16557d3b0d62ee1394de37

gerrit-server/src/main/java/com/google/gerrit/server/project/PutConfig.java

@@ -318,7 +318,7 @@ public class PutConfig implements RestModifyView<ProjectResource, Input> {
   }
 
   private static boolean isValidParameterName(String name) {
-    return CharMatcher.JAVA_LETTER_OR_DIGIT
+    return CharMatcher.javaLetterOrDigit()
         .or(CharMatcher.is('-'))
         .matchesAllOf(name) && !name.startsWith("-");
   }