git-p4: correct hasBranchPrefix verbose output

The logic here was inverted, you got a message saying the file is
ignored for each file that is not ignored.

Signed-off-by: Andrew Oakley <[email protected]>
Acked-by: Lars Schneider <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: aoakley-roku

git-p4.py

@@ -2315,7 +2315,7 @@ def hasBranchPrefix(self, path):
             return True
         hasPrefix = [p for p in self.branchPrefixes
                         if p4PathStartsWith(path, p)]
-        if hasPrefix and self.verbose:
+        if not hasPrefix and self.verbose:
             print('Ignoring file outside of prefix: {0}'.format(path))
         return hasPrefix