Support syncing repositories that utilize Git LFS

The primary usecase of repo is AOSP development, however objects in
AOSP can often get quite large, a lot of firmware and proprietary blobs
can be well above 100 MiB which is the GitHub limit.

src/main/java/hudson/plugins/repo/RepoScm.java

@@ -132,6 +132,7 @@ public class RepoScm extends SCM implements Serializable {
 	@CheckForNull private EnvVars extraEnvVars;
 	@CheckForNull private boolean noCloneBundle;
 	@CheckForNull private boolean worktree;
+	@CheckForNull private boolean gitLfs;
 
 	/**
 	 * Returns the manifest repository URL.
@@ -379,6 +380,13 @@ public boolean isFetchSubmodules() {
 		return fetchSubmodules;
 	}
 
+	/**
+	 * Returns the value of isLfs.
+	 */
+	public boolean isGitLfs() {
+		return gitLfs;
+	}
+
 	/**
 	 * Returns the value of extraEnvVars.
 	 */
@@ -491,6 +499,7 @@ public RepoScm(final String manifestRepositoryUrl) {
 		ignoreProjects = Collections.<String>emptySet();
 		noCloneBundle = false;
 		worktree = false;
+		gitLfs = false;
 	}
 
 	/**
@@ -774,6 +783,18 @@ public void setFetchSubmodules(final boolean fetchSubmodules) {
 		this.fetchSubmodules = fetchSubmodules;
 	}
 
+	/**
+	 * Set gitLfs.
+	 *
+	 * @param gitLfs
+	 *            If this value is true, add the "--git-lfs" option when
+	 *            executing "repo init".
+	 */
+	@DataBoundSetter
+	public void setGitLfs(final boolean gitLfs) {
+		this.gitLfs = gitLfs;
+	}
+
 	/**
 	 * Sets list of projects which changes will be ignored when
 	 * calculating whether job needs to be rebuild. This field corresponds
@@ -1106,6 +1127,9 @@ private boolean checkoutCode(final Launcher launcher,
 		if (manifestSubmodules) {
 			commands.add("--submodules");
 		}
+		if (gitLfs) {
+			commands.add("--git-lfs");
+		}
 		int returnCode =
 				launcher.launch().stdout(logger).pwd(workspace)
 						.cmds(commands).envs(env).join();

src/main/resources/hudson/plugins/repo/RepoScm/config.jelly

@@ -109,5 +109,9 @@
 			<f:checkbox/>
 		</f:entry>
 
+		<f:entry title="Git LFS" field="gitLfs">
+			<f:checkbox default="false"/>
+		</f:entry>
+
 	</f:advanced>
 </j:jelly>

src/main/resources/hudson/plugins/repo/RepoScm/help-gitLfs.html

@@ -0,0 +1,6 @@
+<div>
+    <p>
+        Allow repositories utilizing LFS to sync LFS objects.
+        This is passed to repo as <code>repo init <i>--git-lfs</i></code>.
+    </p>
+</div>