Store build.error_detail in SQL

This should be stored in the SQL database so that the build page
can present the reason why a particular build failed, instead of
just the result "ERROR".

Change-Id: I4dd25546e27b8d3f3a4e049f9980082a3622079f

zuul/driver/sql/alembic/versions/16c1dc9054d0_add_error_detail.py

@@ -0,0 +1,37 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""add error_detail
+
+Revision ID: 16c1dc9054d0
+Revises: 5f183546b39c
+Create Date: 2020-02-25 14:04:56.947095
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '16c1dc9054d0'
+down_revision = '5f183546b39c'
+branch_labels = None
+depends_on = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade(table_prefix=''):
+    op.add_column(
+        table_prefix + 'zuul_build', sa.Column('error_detail', sa.TEXT()))
+
+
+def downgrade():
+    raise Exception("Downgrades not supported")

zuul/driver/sql/sqlconnection.py

@@ -300,6 +300,7 @@ class SQLConnection(BaseConnection):
             voting = sa.Column(sa.Boolean)
             log_url = sa.Column(sa.String(255))
             node_name = sa.Column(sa.String(255))
+            error_detail = sa.Column(sa.TEXT())
             buildset = orm.relationship(BuildSetModel, backref="builds")
 
             def createArtifact(self, *args, **kw):

zuul/driver/sql/sqlreporter.py

@@ -93,6 +93,7 @@ class SQLReporter(BaseReporter):
                     voting=build.job.voting,
                     log_url=log_url,
                     node_name=build.node_name,
+                    error_detail=build.error_detail,
                 )
 
                 for provides in job.provides: