fix in fedora: 7z doesn't support rar archives, use unrar (#370)

see 
https://github.com/ttys3/fedora-rpm-p7zip
https://sourceforge.net/p/sevenzip/discussion/45798/thread/dc2d0438/#8f9f

kindlecomicconverter/comicarchive.py

@@ -39,6 +39,13 @@ class ComicArchive:
                 break
         process.communicate()
         if process.returncode != 0:
+            process = Popen('unrar l -y -p1 "' + self.filepath + '"', stderr=STDOUT, stdout=PIPE, stdin=PIPE, shell=True)
+            for line in process.stdout:
+                if b'Details: ' in line:
+                    self.type = line.rstrip().decode().split(' ')[1].upper()
+                    print(self.type)
+                    break
+            if(self.type != 'RAR'):
                 raise OSError('Archive is corrupted or encrypted.')
         elif self.type not in ['7Z', 'RAR', 'RAR5', 'ZIP']:
             raise OSError('Unsupported archive format.')
@@ -49,6 +56,10 @@ class ComicArchive:
         process = Popen('7z x -y -xr!__MACOSX -xr!.DS_Store -xr!thumbs.db -xr!Thumbs.db -o"' + targetdir + '" "' +
                         self.filepath + '"', stdout=PIPE, stderr=STDOUT, stdin=PIPE, shell=True)
         process.communicate()
+        if process.returncode != 0:
+            process = Popen('unrar x -y -x__MACOSX -x.DS_Store -xthumbs.db -xThumbs.db "' + self.filepath + '" "' +
+                    targetdir + '"', stdout=PIPE, stderr=STDOUT, stdin=PIPE, shell=True)
+            process.communicate()
             if process.returncode != 0:
                 raise OSError('Failed to extract archive.')
         tdir = os.listdir(targetdir)