bpo-12382: Make OpenDatabase() raise better exception messages (GH-4528)

Previously, 'msilib.OpenDatabase()' function raised a
cryptical exception message when it couldn't open or
create an MSI file. For example:

    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    _msi.MSIError: unknown error 6e

PC/_msi.c

@@ -315,6 +315,12 @@ msierror(int status)
         case ERROR_INVALID_PARAMETER:
             PyErr_SetString(MSIError, "invalid parameter");
             return NULL;
+        case ERROR_OPEN_FAILED:
+            PyErr_SetString(MSIError, "open failed");
+            return NULL;
+        case ERROR_CREATE_FAILED:
+            PyErr_SetString(MSIError, "create failed");
+            return NULL;
         default:
             PyErr_Format(MSIError, "unknown error %x", status);
             return NULL;