Fix bug 1722: add support for deploying .charm files

Change-Id: Id43c3d0714cf341dcb4d5581a32d6a1102a3e7ac
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/n2vc/n2vc_juju_conn.py b/n2vc/n2vc_juju_conn.py
index af40aee..c01c436 100644
--- a/n2vc/n2vc_juju_conn.py
+++ b/n2vc/n2vc_juju_conn.py
@@ -453,7 +453,7 @@
             artifact_path = artifact_path.replace("//", "/")
 
         # check charm path
-        if not self.fs.file_exists(artifact_path, mode="dir"):
+        if not self.fs.file_exists(artifact_path):
             msg = "artifact path does not exist: {}".format(artifact_path)
             raise N2VCBadArgumentsException(message=msg, bad_args=["artifact_path"])
 
@@ -550,7 +550,7 @@
             artifact_path = artifact_path.replace("//", "/")
 
         # check charm path
-        if not self.fs.file_exists(artifact_path, mode="dir"):
+        if not self.fs.file_exists(artifact_path):
             msg = "artifact path does not exist: {}".format(artifact_path)
             raise N2VCBadArgumentsException(message=msg, bad_args=["artifact_path"])