bpo-43920: Make load_verify_locations(cadata) error message consistent (GH-25554)

Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index 0b8cef6..8c84657 100644
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -1433,12 +1433,17 @@ def test_load_verify_cadata(self):
         ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
         self.assertRaises(TypeError, ctx.load_verify_locations, cadata=object)
 
-        with self.assertRaisesRegex(ssl.SSLError, "no start line"):
+        with self.assertRaisesRegex(
+            ssl.SSLError,
+            "no start line: cadata does not contain a certificate"
+        ):
             ctx.load_verify_locations(cadata="broken")
-        with self.assertRaisesRegex(ssl.SSLError, "not enough data"):
+        with self.assertRaisesRegex(
+            ssl.SSLError,
+            "not enough data: cadata does not contain a certificate"
+        ):
             ctx.load_verify_locations(cadata=b"broken")
 
-
     @unittest.skipIf(Py_DEBUG_WIN32, "Avoid mixing debug/release CRT on Windows")
     def test_load_dh_params(self):
         ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)