change the pandoc download logic

setup.py

@@ -7,19 +7,17 @@ import pypandoc
 
 long_description = ""
 
-try:
-    long_description = pypandoc.convert('README.md', 'rst')
-except OSError as e:
-    print("Pypandoc import failed, trying to download pancdoc...")
-    pypandoc.download_pandoc()
-
-print("Trying to convert again...")
+print("Trying to download pandoc...")
+pypandoc.download_pandoc()
 
 try:
     long_description = pypandoc.convert('README.md', 'rst')
 except OSError as e:
-    print("Readme conversion failed.")
-    sys.exit(1)
+    print("Pandoc not found.")
+    import io
+    # pandoc is not installed, fallback to using raw contents
+    with io.open('README.md', encoding="utf-8") as f:
+        long_description = f.read()
 
 # cv_version.py should be generated by running find_version.py
 from cv_version import opencv_version