package daemon: Rework error and issue propagation to client

* BDaemonClient: Move inner class BCommitTransactionResult to top level
  and make it public.
* BCommitTransactionResult:
  - Add a whole bunch of specific error code enum values. Such an error
    code is now the primary error, as opposed to before where we would
    mix status_t and enum value errors. There's a systemError property
    of type status_t which may provide additional information, though
    (depending on the primary error type).
  - Remove the errorMessage property. Due to mapping all errors to the
    specific error codes this is no longer necessary. Mixing such a
    message with another error description is also not very helpful when
    it comes to localization (still not supported, though).
  - Add several properties (paths, strings, error codes) that serve as
    arguments to the primary error and are used by FullErrorMessage().
  - Add issues property, a list of instances of new class
    BTransactionIssue. Those describe non-critical issues (e.g. failed
    update of a settings file) that occurred in the process of
    committing the transaction. Those issues should be presented to the
    user by the package management program.
* Exception: Adjust to transport the BCommitTransactionResult
  properties.
* CommitTransactionHandler, FsTransactions, Root, Volume: Adjust to
  BCommitTransactionResult/Exception changes.
* CommitTransactionHandler: Now requires a BCommitTransactionResult to
  which it adds the issues it encounters. The reply BMessage is no
  longer needed, though.
* Volume: Refactor common code from the three methods that use
  CommitTransactionHandler into new method _CommitTransaction.

headers/private/package/DaemonClient.h

@@ -22,6 +22,7 @@ class BDirectory;
 namespace BPackageKit {
 
 
+class BCommitTransactionResult;
 class BInstallationLocationInfo;
 class BPackageInfoSet;
 
@@ -33,9 +34,6 @@ class BActivationTransaction;
 
 
 class BDaemonClient {
-public:
-			class BCommitTransactionResult;
-
 public:
 								BDaemonClient();
 								~BDaemonClient();
@@ -65,41 +63,6 @@ private:
 };
 
 
-class BDaemonClient::BCommitTransactionResult {
-public:
-								BCommitTransactionResult();
-								BCommitTransactionResult(int32 error,
-									const BString& errorMessage,
-									const BString& errorPackage,
-									const BString& oldStateDirectory);
-								~BCommitTransactionResult();
-
-			void				SetTo(int32 error, const BString& errorMessage,
-									const BString& errorPackage,
-									const BString& oldStateDirectory);
-
-			status_t			Error() const;
-			BDaemonError		DaemonError() const;
-									// may be B_DAEMON_OK, even if Error() is
-									// != B_OK, then Error() is as specific as
-									// is known
-			const BString&		ErrorMessage() const;
-									// may be empty, even on error
-			const BString&		ErrorPackage() const;
-									// may be empty, even on error
-
-			BString				FullErrorMessage() const;
-
-			const BString&		OldStateDirectory() const;
-
-private:
-			int32				fError;
-			BString				fErrorMessage;
-			BString				fErrorPackage;
-			BString				fOldStateDirectory;
-};
-
-
 }	// namespace BPrivate
 }	// namespace BPackageKit