Bug 1609 fix

This patch changes the behaviour of native charm deployments.
it  won't deploy another application for the same vnf or
vdu charm at initial deployment or scaling process.
It scales the application.

Change-Id: I3fc52a5ddb0cb7cb16937bc12cf343f7d869c9ee
Signed-off-by: aktas <emin.aktas@ulakhaberlesme.com.tr>
(cherry picked from commit fa02f8a90b7fe1e1b7a80feedef4132bef1ca3e4)
diff --git a/n2vc/exceptions.py b/n2vc/exceptions.py
index 1f48661..9867cb9 100644
--- a/n2vc/exceptions.py
+++ b/n2vc/exceptions.py
@@ -111,6 +111,18 @@
         return "<{}> Not found: {}".format(type(self), super().__str__())
 
 
+class N2VCApplicationExists(N2VCException):
+    """
+    Application Exists
+    """
+
+    def __init__(self, message: str = ""):
+        N2VCException.__init__(self, message=message)
+
+    def __str__(self):
+        return "<{}> Application Exists: {}".format(type(self), super().__str__())
+
+
 class JujuError(N2VCException):
     """
     Juju Error