HaikuDepot: Log more errors to stderr.

These errors do not necessarily need to be reported to the user via alerts.
They are more of an indication that HaikuDepot needs to be smarter when
figuring out what package actions to present at all.

src/apps/haikudepot/model/PackageManager.cpp

@@ -127,9 +127,13 @@ public:
 				alert->Go(NULL);
 			return ex.Error();
 		} catch (BAbortedByUserException ex) {
+			fprintf(stderr, "Installation of package "
+				"%s aborted by user: %s\n", packageName, ex.Message().String());
 			_SetDownloadedPackagesState(NONE);
 			return B_OK;
 		} catch (BNothingToDoException ex) {
+			fprintf(stderr, "Nothing to do while installing package "
+				"%s: %s\n", packageName, ex.Message().String());
 			return B_OK;
 		} catch (BException ex) {
 			fprintf(stderr, "Exception occurred while installing package "