Upgrade JGit to 5.1.3.201810200350-r

Includes the following fixes since 5.1.2.201810061102-r:

- SubmoduleValidator: Permit missing path or url
- Fix file handle leak in ObjectDownloadListener.onWritePossible
- ssh: Prefer algorithms of the known host keys

Change-Id: Iab12e96052f7bb4ad6a3715282d8a5077801f3ae

lib/jgit/jgit.bzl

@@ -1,6 +1,6 @@
 load("//tools/bzl:maven_jar.bzl", "GERRIT", "MAVEN_CENTRAL", "MAVEN_LOCAL", "maven_jar")
 
-_JGIT_VERS = "5.1.2.201810061102-r"
+_JGIT_VERS = "5.1.3.201810200350-r"
 
 _DOC_VERS = _JGIT_VERS  # Set to _JGIT_VERS unless using a snapshot
 
@@ -40,28 +40,28 @@ def jgit_maven_repos():
         name = "jgit-lib",
         artifact = "org.eclipse.jgit:org.eclipse.jgit:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "467c951f20aef345c584e1d578be691ac7ae6fbc",
-        src_sha1 = "37a8b0233413af35886be512ebfcd499a439d455",
+        sha1 = "f270dbd1d792d5ad06074abe018a18644c90b60e",
+        src_sha1 = "00e24ee2b721040edbb8520d705607a7f7bafd64",
         unsign = True,
     )
     maven_jar(
         name = "jgit-servlet",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.http.server:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "f8a7f7934b8038fe01f26a0908b648385dbc5ffe",
+        sha1 = "360405244c28b537f0eafdc0b9d9f3753503d981",
         unsign = True,
     )
     maven_jar(
         name = "jgit-archive",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.archive:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "c51089a2e1f225f4b10e78e9bfc9c077a9337977",
+        sha1 = "08e10921fcc75ead2736dd5bf099ba8e2ed8a3fb",
     )
     maven_jar(
         name = "jgit-junit",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.junit:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "afd35253f780ffb64281bcb3abfe24cceef78d2e",
+        sha1 = "1dc8f86bba3c461cb90c9dc3e91bf343889ca684",
         unsign = True,
     )