pgm: propagate generic exceptions when throwing Die exception

If a command is stopped by throwing a Die exception since a generic
exception was caught this exception contains additional information
which is not available in the error message. Hence chain it to the Die
exception in order to allow printing a complete stacktrace including
causes to the error stream of the JGit command line by adding option
--show-stack-trace, e.g.

$ jgit --show-stack-trace commit -m "test"

Change-Id: I7ad8c56b997ab60d2bd08f4e7b4d0b80c84021c3
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Archive.java

@@ -96,11 +96,11 @@ class Archive extends TextBuiltin {
 				if (output != null)
 					cmd.setFilename(output);
 				cmd.call();
-		} catch (GitAPIException e) {
-			throw die(e.getMessage());
-		}
+			} catch (GitAPIException e) {
+				throw die(e.getMessage(), e);
+			}
 		} catch (FileNotFoundException e) {
-			throw die(e.getMessage());
+			throw die(e.getMessage(), e);
 		} finally {
 			if (output != null && stream != null)
 				stream.close();

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java

@@ -110,7 +110,7 @@ class Clone extends AbstractFetchCommand implements CloneCommand.Callback {
 						Constants.OS_USER_DIR), localName);
 			} catch (IllegalArgumentException e) {
 				throw die(MessageFormat.format(
-						CLIText.get().cannotGuessLocalNameFrom, sourceUri));
+						CLIText.get().cannotGuessLocalNameFrom, sourceUri), e);
 			}
 		} else
 			localNameF = new File(localName);

org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/TextBuiltin.java

@@ -196,7 +196,7 @@ public abstract class TextBuiltin {
 				try {
 					return Charset.forName(logOutputEncoding);
 				} catch (IllegalArgumentException e) {
-					throw die(CLIText.get().cannotCreateOutputStream);
+					throw die(CLIText.get().cannotCreateOutputStream, e);
 				}
 			}
 		}