res_pjsip: New endpoint option "notify_early_inuse_ringing"

This option was added to control whether to notify dialog-info state
'early' or 'confirmed' on Ringing when already INUSE.
The value "yes" is useful for some SIP phones (Cisco SPA)
to be able to indicate and pick up ringing devices.

ASTERISK-26919 #close

Change-Id: Ie050bc30023543c7dfb4365c5be3ce58c738c711

contrib/ast-db-manage/config/versions/d7983954dd96_add_ps_endpoints_notify_early_inuse_.py

@@ -0,0 +1,30 @@
+"""add ps_endpoints.notify_early_inuse_ringing
+
+Revision ID: d7983954dd96
+Revises: 86bb1efa278d
+Create Date: 2017-06-05 15:44:41.152280
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'd7983954dd96'
+down_revision = '86bb1efa278d'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import ENUM
+
+YESNO_NAME = 'yesno_values'
+YESNO_VALUES = ['yes', 'no']
+
+def upgrade():
+    ############################# Enums ##############################
+
+    # yesno_values have already been created, so use postgres enum object
+    # type to get around "already created" issue - works okay with mysql
+    yesno_values = ENUM(*YESNO_VALUES, name=YESNO_NAME, create_type=False)
+
+    op.add_column('ps_endpoints', sa.Column('notify_early_inuse_ringing', yesno_values))
+
+def downgrade():
+    op.drop_column('ps_endpoints', 'notify_early_inuse_ringing')