Skip personality max limit tests in case no limit

If number of personality file limit is set to -1, it means no limit.

This patch skips personality max limit tests in
above case.

Change-Id: I2808deae9c48bb0baa108b9fded2831c6c02935f
diff --git a/tempest/api/compute/servers/test_server_personality.py b/tempest/api/compute/servers/test_server_personality.py
index de5b6c1..c6d48bc 100644
--- a/tempest/api/compute/servers/test_server_personality.py
+++ b/tempest/api/compute/servers/test_server_personality.py
@@ -36,6 +36,8 @@
         personality = []
         max_file_limit = \
             self.user_client.get_specific_absolute_limit("maxPersonality")
+        if max_file_limit == -1:
+            raise self.skipException("No limit for personality files")
         for i in range(0, int(max_file_limit) + 1):
             path = 'etc/test' + str(i) + '.txt'
             personality.append({'path': path,
@@ -52,6 +54,8 @@
         file_contents = 'This is a test file.'
         max_file_limit = \
             self.user_client.get_specific_absolute_limit("maxPersonality")
+        if max_file_limit == -1:
+            raise self.skipException("No limit for personality files")
         person = []
         for i in range(0, int(max_file_limit)):
             path = 'etc/test' + str(i) + '.txt'