Move a few variables around

This should prevent a couple of crashes
due to undeclared variables.

cps/comic.py

@@ -37,9 +37,9 @@ except ImportError as e:
 
 
 def extractCover(tmp_file_name, original_file_extension):
+    cover_data = extension = None
     if use_comic_meta:
         archive = ComicArchive(tmp_file_name)
-        cover_data = None
         for index, name in enumerate(archive.getPageNameList()):
             ext = os.path.splitext(name)
             if len(ext) > 1:

cps/constants.py

@@ -101,8 +101,8 @@ DEFAULT_MAIL_SERVER = "mail.example.org"
 
 DEFAULT_PASSWORD    = "admin123"
 DEFAULT_PORT        = 8083
-try:
 env_CALIBRE_PORT = os.environ.get("CALIBRE_PORT", DEFAULT_PORT)
+try:
     DEFAULT_PORT = int(env_CALIBRE_PORT)
 except ValueError:
     print('Environment variable CALIBRE_PORT has invalid value (%s), faling back to default (8083)' % env_CALIBRE_PORT)

cps/helper.py

@@ -303,8 +303,8 @@ def update_dir_structure_file(book_id, calibrepath, first_author):
     new_titledir = get_valid_filename(localbook.title) + " (" + str(book_id) + ")"
 
     if titledir != new_titledir:
-        try:
         new_title_path = os.path.join(os.path.dirname(path), new_titledir)
+        try:
             if not os.path.exists(new_title_path):
                 os.renames(path, new_title_path)
             else:
@@ -321,8 +321,8 @@ def update_dir_structure_file(book_id, calibrepath, first_author):
             return _("Rename title from: '%(src)s' to '%(dest)s' failed with error: %(error)s",
                      src=path, dest=new_title_path, error=str(ex))
     if authordir != new_authordir:
-        try:
         new_author_path = os.path.join(calibrepath, new_authordir, os.path.basename(path))
+        try:
             os.renames(path, new_author_path)
             localbook.path = new_authordir + '/' + localbook.path.split('/')[1]
         except OSError as ex: