Bump SLF4J to 1.7.33 for including Reload4J binding

The SLF4J's MDC  has been broken since the swap
of Log4J with Reload4J done in Change I1d01ab0a5d3a.

Although Reload4J is supposed to be a replacement for Log4J
some of its internals are different with regards to the
MDC's initialization.

SF4J assumes that the MDC's structure is the one implemented
in Log4J; however, when the Reload4J classes are used, it\
fails with java.lang.NoSuchFieldError: tlm.

The failure is subtle because it appears only when one of
the classes Gerrit's plugins directly refers
to the MDC. The Gerrit build instead does not instantly
fail, even if there is a mismatch of SLF4J binding.

The SLF4J project has created a specific binding for Reload4J
that is available from v1.7.33 (see [1]), hence the bump
of release and the swap of Log4J with Reload4J also on the
binding side.

[1] https://mvnrepository.com/artifact/org.slf4j/slf4j-reload4j/1.7.33

Bug: Issue 15590
Change-Id: Icef4a845d5a9539e396698853e810334ea6b036b
diff --git a/WORKSPACE b/WORKSPACE
index bba5818..3b8b768 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -228,30 +228,30 @@
     sha1 = "28c59f58f5adcc307604602e2aa89e2aca14c554",
 )
 
-SLF4J_VERS = "1.7.26"
+SLF4J_VERS = "1.7.33"
 
 maven_jar(
     name = "log-api",
     artifact = "org.slf4j:slf4j-api:" + SLF4J_VERS,
-    sha1 = "77100a62c2e6f04b53977b9f541044d7d722693d",
+    sha1 = "d375aa1b98d34d5ddf73a3f19eaad66e98975b12",
 )
 
 maven_jar(
     name = "log-ext",
     artifact = "org.slf4j:slf4j-ext:" + SLF4J_VERS,
-    sha1 = "31cdf122e000322e9efcb38913e9ab07825b17ef",
+    sha1 = "00da03640ae1ad57f964dcaa542fb5d804dce8a6",
 )
 
 maven_jar(
     name = "impl-log4j",
-    artifact = "org.slf4j:slf4j-log4j12:" + SLF4J_VERS,
-    sha1 = "12f5c685b71c3027fd28bcf90528ec4ec74bf818",
+    artifact = "org.slf4j:slf4j-reload4j:" + SLF4J_VERS,
+    sha1 = "ddc89144bfb56781936120b2334a70869b68db6d",
 )
 
 maven_jar(
     name = "jcl-over-slf4j",
     artifact = "org.slf4j:jcl-over-slf4j:" + SLF4J_VERS,
-    sha1 = "33fbc2d93de829fa5e263c5ce97f5eab8f57d53e",
+    sha1 = "28c441128bc81b6d95cc2857ae5bb46ae5bf658b",
 )
 
 maven_jar(