Upgrade javassist.jar to 3.18.1

Upgraded dependency for javassist.jar from 3.17.1 to 3.18.1
to allow powermock unit tests involving RevCommit.class to complete.
Problem started to appear after Change-Id: Ib4c82bbcf of 22-January
See https://issues.jboss.org/browse/JASSIST-190 for info on the bug
being fixed (related to multicatch syntax in java7 introduced in latest
RevCommit class)

Change-Id: I9286a6892ba3e9af14d579e91cdbfcdc08b170f8

lib/BUCK

@@ -253,10 +253,9 @@ maven_jar(
 )
 
 maven_jar(
-  name = 'javassist-3.17.1-GA',
-  # The GWT version is still at 3.16.1-GA, so those do not match
-  id = 'org.javassist:javassist:3.17.1-GA',
-  sha1 = '30c30512115866b6e0123f1913bc7735b9f76d08',
+  name = 'javassist',
+  id = 'org.javassist:javassist:3.18.1-GA',
+  sha1 = 'd9a09f7732226af26bf99f19e2cffe0ae219db5b',
   license = 'DO_NOT_DISTRIBUTE',
 )
 

lib/powermock/BUCK

@@ -66,7 +66,7 @@ maven_jar(
   license = 'DO_NOT_DISTRIBUTE',
   deps = [
     ':powermock-reflect',
-    '//lib:javassist-3.17.1-GA',
+    '//lib:javassist',
     '//lib:junit',
   ],
 )