Fixed issue of system exiting during active session

When the entire OS halts during the middle of a pappy crypto
session, the `crypt` working directory is left unencrypted.
To fix this, I added another conditional into `crypto.py`'s
decryption function to enter an existing crypto working directory,
so that when the project finishes it will encrypt/exit properly.

pappyproxy/crypto.py

@@ -61,19 +61,8 @@ class Crypto(object):
         Decrypt and decompress the project files
         """
 
-        # If project hasn't been encrypted before,
-        # setup crypt working directory
-        if not os.path.isfile(self.config.crypt_file):
-            os.mkdir(self.config.crypt_dir)
-
-            project_files = self.config.get_project_files()
-            for pf in project_files:
-                shutil.copy2(pf, self.config.crypt_dir)
-            os.chdir(self.config.crypt_dir)
-            return True
-
-        # Otherwise, decrypt and decompress the project
-        else:
+        # Decrypt and decompress the project if crypt_file exists
+        if os.path.isfile(self.config.crypt_file):
             archive_crypt = open(self.config.crypt_file, 'rb').read()
             archive_file = open(self.config.archive, 'wb')
 
@@ -109,6 +98,22 @@ class Crypto(object):
             os.chdir(self.config.crypt_dir)
             self.config.crypt_success = True
             return True
+        # If project exited before encrypting the working directory
+        # change to the working directory to resume the session
+	elif os.path.isdir(self.config.crypt_dir):
+            os.chdir(self.config.crypt_dir)
+            return True
+        # If project hasn't been encrypted before,
+        # setup crypt working directory
+        else:
+            os.mkdir(self.config.crypt_dir)
+
+            project_files = self.config.get_project_files()
+            for pf in project_files:
+                shutil.copy2(pf, self.config.crypt_dir)
+            os.chdir(self.config.crypt_dir)
+            return True
+
 
     def confirm_password_retry(self):
         answer = raw_input("Re-enter your password? (y/n)").strip()