pjsip: Add option global/regcontext

Added new global option (regcontext) to pjsip. When set, Asterisk will
dynamically create and destroy a NoOp priority 1 extension
for a given endpoint who registers or unregisters with us.

ASTERISK-25670 #close
Reported-by: Daniel Journo

Change-Id: Ib1530c5b45340625805c057f8ff1fb240a43ea62

contrib/ast-db-manage/config/versions/136885b81223_add_regcontext_to_pj.py

@@ -0,0 +1,20 @@
+"""add regcontext to pjsip
+
+Revision ID: 136885b81223
+Revises: 2d078ec071b7
+Create Date: 2016-01-11 22:32:45.470522
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '136885b81223'
+down_revision = '2d078ec071b7'
+
+from alembic import op
+import sqlalchemy as sa
+
+def upgrade():
+    op.add_column('ps_globals', sa.Column('regcontext', sa.String(80)))
+
+def downgrade():
+    op.drop_column('ps_globals', 'regcontext')