Update various lib dependencies

Mostly to match the current versions in Gerrit Code Review. Leave
Guava for now as it requires a bit more work.

Change-Id: I6151c50d545efb2c18fde193f88b5a74acd18ecf

lib/slf4j/BUCK

diff --git a/lib/slf4j/BUCK b/lib/slf4j/BUCK
index 4d43e55..877deed 100644
--- a/lib/slf4j/BUCK
+++ b/lib/slf4j/BUCK
@@ -1,9 +1,9 @@
-VERS = '1.6.1'
+VERS = '1.7.7'
 
 maven_jar(
   name = 'slf4j-api',
   id = 'org.slf4j:slf4j-api:' + VERS,
-  sha1 = '6f3b8a24bf970f17289b234284c94f43eb42f0e4',
+  sha1 = '2b8019b6249bb05d81d3a3094e468753e2b21311',
   visibility = ['PUBLIC'],
 )
 
@@ -11,7 +11,7 @@
 maven_jar(
   name = 'slf4j-simple',
   id = 'org.slf4j:slf4j-simple:' + VERS,
-  sha1 = '58e59bfb3e247097b8122243b3bfe0049c8cfae8',
+  sha1 = '8095d0b9f7e0a9cd79a663c740e0f8fb31d0e2c8',
   deps = [':slf4j-api'],
   visibility = ['PUBLIC'],
 )