Upgrade JGit to 4.7.3.201809090215-r

This release includes the following fixes since 4.7.2.201807261330-r:

- Fix atomic lock file creation on NFS
- Fix handling of option core.supportsAtomicCreateNewFile
- GC: Avoid logging errors when deleting non-empty folders
- Fix GC run in foreground to not use executor

Change-Id: I6862cd6c3bff5b07234d886f80fb42504dd1ca79
diff --git a/lib/jgit/jgit.bzl b/lib/jgit/jgit.bzl
index 960b12b..f9a2085 100644
--- a/lib/jgit/jgit.bzl
+++ b/lib/jgit/jgit.bzl
@@ -1,6 +1,6 @@
 load("//tools/bzl:maven_jar.bzl", "GERRIT", "MAVEN_CENTRAL", "MAVEN_LOCAL", "maven_jar")
 
-_JGIT_VERS = "4.7.2.201807261330-r"
+_JGIT_VERS = "4.7.3.201809090215-r"
 
 _DOC_VERS = _JGIT_VERS  # Set to _JGIT_VERS unless using a snapshot
 
@@ -35,28 +35,28 @@
         name = "jgit-lib",
         artifact = "org.eclipse.jgit:org.eclipse.jgit:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "6c08ef848fa5f7d5d49776fa25ec24d738ee457d",
-        src_sha1 = "ee14417c135693ddc1eebcf23b8cb661c9b8387d",
+        sha1 = "81b7a1a7484ce0519298e388cab97082e2d20c97",
+        src_sha1 = "5e14588b33defc5da2f0179c7c7b42343d8836e0",
         unsign = True,
     )
     maven_jar(
         name = "jgit-servlet",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.http.server:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "2bde0520c1831eedff5d8e0347e254edc8bf9fa1",
+        sha1 = "8113a2bd4b426e12eda75a0f79438a58775feaab",
         unsign = True,
     )
     maven_jar(
         name = "jgit-archive",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.archive:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "a0ad9edcd5dc5ba2cf54dfaaa542e520e771d2b8",
+        sha1 = "14fe9c4f2bbfb78e66e3524a2ee6a86336ed957d",
     )
     maven_jar(
         name = "jgit-junit",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.junit:" + _JGIT_VERS,
         repository = _JGIT_REPO,
-        sha1 = "ef8a52ff0a7afcecdb6338b00b03b9a0e0f53dae",
+        sha1 = "d17e6e24dc7b8cbbf8a95235f51cc47bb8669519",
         unsign = True,
     )