Move included subdomain lists from data_files to package_data

Data included under package_data is better suite for files that will be
referenced by code within the package. This is what Fierce does, so
let's use package_data.

fierce.py

@@ -38,28 +38,16 @@ def find_subdomain_list_file(filename):
     #
     #     https://github.com/pypa/pip/blob/master/pip/commands/show.py
     #
+    package_filename_path = os.path.join("lists", filename)
     try:
-        fierce = pkg_resources.get_distribution('fierce')
-    except pkg_resources.DistributionNotFound:
+        full_package_path = pkg_resources.resource_filename(
+            'fierce',
+            package_filename_path
+        )
+    except ImportError:
         return filename
 
-    if isinstance(fierce, pkg_resources.Distribution):
-        paths = []
-        if fierce.has_metadata('RECORD'):
-            lines = fierce.get_metadata_lines('RECORD')
-            paths = [l.split(',')[0] for l in lines]
-            paths = [os.path.join(fierce.location, p) for p in paths]
-        elif fierce.has_metadata('installed-files.txt'):
-            lines = fierce.get_metadata_lines('installed-files.txt')
-            paths = [l for l in lines]
-            paths = [os.path.join(fierce.egg_info, p) for p in paths]
-
-        for p in paths:
-            if filename == os.path.basename(p):
-                return p
-
-    # If we couldn't find anything just return the original list file
-    return filename
+    return full_package_path
 
 
 def head_request(url, timeout=2):
@@ -186,7 +174,13 @@ def get_stripped_file_lines(filename):
     """
     Return lines of a file with whitespace removed
     """
-    return [line.strip() for line in open(filename).readlines()]
+    try:
+        lines = [line.strip() for line in open(filename).readlines()]
+    except FileNotFoundError:
+        print("Could not find subdomain file '{}'".format(filename))
+        return []
+
+    return lines
 
 
 def get_subdomains(subdomains, subdomain_filename):

setup.py

@@ -44,7 +44,9 @@
             'fierce = fierce:main',
         ],
     },
-    data_files=[
-        ('lists', data_files_lists),
-    ],
+    package_data={
+        'fierce': [
+            'lists/*',
+        ]
+    },
 )