Add OM System MakerNote test

(manually adapted from 18e2b9a)

Author: kmilos

test/data/test_issue_2126.exv

@@ -0,0 +1,15 @@
+from system_tests import CaseMeta, path
+
+class OMSystemMakerNote(metaclass=CaseMeta):
+    """
+    Regression test for the bug described in:
+    https://github.com/Exiv2/exiv2/issues/2126
+    """
+    url = "https://github.com/Exiv2/exiv2/issues/2126"
+
+    filename = path("$data_path/test_issue_2126.exv")
+    commands = ["$exiv2 -q -K Exif.Olympus2.CameraID $filename"]
+    stdout = ["""Exif.Olympus2.CameraID                       Undefined  32  OM SYSTEM CAMERA               
+"""]
+    stderr = [""]
+    retval = [0]