Improved creation of JGitInternalException

There where 3 cases where a JGitInternalExcption was created
without specifying the root cause. This has been fixed.

Change-Id: I2ee08d04732371cd9e30874b1437b61217770b6a
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java

@@ -248,7 +248,7 @@ public class CommitCommand extends GitCommand<RevCommit> {
 			} catch (IOException e) {
 				throw new JGitInternalException(MessageFormat.format(
 						JGitText.get().exceptionOccuredDuringReadingOfGIT_DIR,
-						Constants.MERGE_HEAD, e));
+						Constants.MERGE_HEAD, e), e);
 			}
 			if (message == null) {
 				try {
@@ -256,7 +256,7 @@ public class CommitCommand extends GitCommand<RevCommit> {
 				} catch (IOException e) {
 					throw new JGitInternalException(MessageFormat.format(
 							JGitText.get().exceptionOccuredDuringReadingOfGIT_DIR,
-							Constants.MERGE_MSG, e));
+							Constants.MERGE_MSG, e), e);
 				}
 			}
 		}

org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java

@@ -164,7 +164,7 @@ public class MergeCommand extends GitCommand<MergeResult> {
 			throw new JGitInternalException(
 					MessageFormat.format(
 							JGitText.get().exceptionCaughtDuringExecutionOfMergeCommand,
-							e));
+							e), e);
 		}
 	}