Fixed a sporadic failure in test_delete_share_in_manage_error

Added the prefix, '-share-protocol' to 'export_path' resulting in
a unique export path value per share protocol.

Change-Id: I57fbfb0199a38235efaa6b1c2a08e0318180318f
diff --git a/manila_tempest_tests/tests/api/admin/test_share_manage_negative.py b/manila_tempest_tests/tests/api/admin/test_share_manage_negative.py
index d5cc09f..06d429b 100644
--- a/manila_tempest_tests/tests/api/admin/test_share_manage_negative.py
+++ b/manila_tempest_tests/tests/api/admin/test_share_manage_negative.py
@@ -258,7 +258,9 @@
 
         # forge bad param to have a share in manage_error state
         invalid_params = valid_params.copy()
-        invalid_params.update({'export_path': 'invalid'})
+        invalid_params.update(
+            {'export_path': 'invalid-%s-share' % self.protocol}
+        )
         invalid_share = self.shares_v2_client.manage_share(**invalid_params)
 
         waiters.wait_for_share_status(