Remove test for Pillow JPEG and PNG

As of 3.1.1, our minimum version, these codecs are now required by
default for a successful installation, effectively solving the problem
of Pillow installed without libjpeg/libpng.

ocrmypdf/__main__.py

@@ -67,40 +67,6 @@ if tesseract.version() < MINIMUM_TESS_VERSION:
             MINIMUM_TESS_VERSION, tesseract.version()))
     sys.exit(ExitCode.missing_dependency)
 
-try:
-    import PIL.features
-    check_codec = PIL.features.check_codec
-except (ImportError, AttributeError):
-    def check_codec(codec_name):
-        if codec_name == 'jpg':
-            return 'jpeg_encoder' in dir(Image.core)
-        elif codec_name == 'zlib':
-            return 'zip_encoder' in dir(Image.core)
-        raise NotImplementedError(codec_name)
-
-
-def check_pil_encoder(codec_name, friendly_name):
-    try:
-        if check_codec(codec_name):
-            return
-    except Exception:
-        pass
-    complain(
-        "ERROR: Your version of the Python imaging library (Pillow) was "
-        "compiled without support for " + friendly_name + " encoding/decoding."
-        "\n"
-        "You will need to uninstall Pillow and reinstall it with PNG and JPEG "
-        "support (libjpeg and zlib)."
-        "\n"
-        "See installation instructions for your platform here:\n"
-        "    https://pillow.readthedocs.org/installation.html"
-    )
-    sys.exit(ExitCode.missing_dependency)
-
-
-check_pil_encoder('jpg', 'JPEG')
-check_pil_encoder('zlib', 'PNG')
-
 
 # -------------
 # Parser