core: extend installed_by column size in schema...

Extend installed_by column size in schema version

Extend installed_by column size to 64 to match definition in pg_user.

Change-Id: I1483f3fb5f4e5945d1b5d26a12fb24c01ac3c08d
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1070742
Signed-off-by: Eli Mesika <emesika@redhat.com>