Change -vars-file to -var-file

Changed vars_file to var_file to bring it into line with packer syntax, documentation will also need updating. Will submit a pull request for that in a second

Author: andyjp94

packer/__init__.py

@@ -12,17 +12,17 @@ class Packer():
     """Packer interface using the `sh` module (http://amoffat.github.io/sh/)
     """
     def __init__(self, packerfile, exc=None, only=None, vars=None,
-                 vars_file=None, exec_path=DEFAULT_PACKER_PATH):
+                 var_file=None, exec_path=DEFAULT_PACKER_PATH):
         """
         :param string packerfile: Path to Packer template file
         :param list exc: List of builders to exclude
         :param list only: List of builders to include
         :param dict vars: Key Value pairs of template variables
-        :param string vars_file: Path to variables file
+        :param string var_file: Path to variables file
         :param string exec_path: Path to Packer executable
         """
         self.packerfile = self._validate_argtype(packerfile, str)
-        self.vars_file = vars_file
+        self.var_file = var_file
         if not os.path.isfile(self.packerfile):
             raise OSError('packerfile not found at path: {0}'.format(
                 self.packerfile))
@@ -157,7 +157,7 @@ def _validate_argtype(self, arg, argtype):
     def _append_base_arguments(self):
         """Appends base arguments to packer commands.
 
-        -except, -only, -var and -vars-file are appeneded to almost
+        -except, -only, -var and -var-file are appeneded to almost
         all subcommands in packer. As such this can be called to add
         these flags to the subcommand.
         """
@@ -169,8 +169,8 @@ def _append_base_arguments(self):
             self._add_opt('-only={0}'.format(self._joinc(self.only)))
         for var, value in self.vars.items():
             self._add_opt("-var '{0}={1}'".format(var, value))
-        if self.vars_file:
-            self._add_opt('-vars-file={0}'.format(self.vars_file))
+        if self.var_file:
+            self._add_opt('-var-file={0}'.format(self.var_file))
 
     def _joinc(self, lst):
         """Returns a comma delimited string from a list"""