Add constructors that take Throwable to ServiceMayNotContinueException.

ServiceMayNotContinueException usually wraps an underlying exception.
Add convenience constructors that take Throwable. In the case a
string is not provided, the message defaults to "internal server error",
since it may be reported to the client.

Change-Id: I15dc20306826c352f69e88afb7ed6927c12b6c1f

org.eclipse.jgit/src/org/eclipse/jgit/transport/ServiceMayNotContinueException.java

@@ -45,6 +45,8 @@ package org.eclipse.jgit.transport;
 
 import java.io.IOException;
 
+import org.eclipse.jgit.internal.JGitText;
+
 /**
  * Indicates a transport service may not continue execution.
  *
@@ -69,6 +71,27 @@ public class ServiceMayNotContinueException extends IOException {
 		super(msg);
 	}
 
+	/**
+	 * @param msg
+	 *            a message explaining why it cannot continue. This message may
+	 *            be shown to an end-user.
+	 * @param cause
+	 *            the cause of the exception.
+	 */
+	public ServiceMayNotContinueException(String msg, Throwable cause) {
+		super(msg, cause);
+	}
+
+	/**
+	 * Initialize with an "internal server error" message and a cause.
+	 *
+	 * @param cause
+	 *            the cause of the exception.
+	 */
+	public ServiceMayNotContinueException(Throwable cause) {
+		super(JGitText.get().internalServerError, cause);
+	}
+
 	/** @return true if the message was already output to the client. */
 	public boolean isOutput() {
 		return output;