Alembic: Increase column size of PJSIP AOR "contact".

When running the PJSIP AMI "show_endpoint" test with automatic
conversion to realtime, the test would fail. This was because the AOR
"contact" column was sized at 40, and the configured contact was larger
than that.

This commit increases the size of the contact column to 255 characters.

Change-Id: Ia65bc7fd37699b7c0eaef9629a1a31eab9a24ba1

contrib/ast-db-manage/config/versions/2d078ec071b7_increaes_contact_column_size.py

+"""increaes_contact_column_size
+
+Revision ID: 2d078ec071b7
+Revises: 189a235b3fd7
+Create Date: 2015-12-16 11:26:54.218985
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '2d078ec071b7'
+down_revision = '189a235b3fd7'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.alter_column('ps_aors', 'contact', type_=sa.String(255))
+
+
+def downgrade():
+    op.alter_column('ps_aors', 'contact', type_=sa.String(40))