Merge the tip of origin/release/proposed/2019.2.0 into origin/release/2019.2.0

b33cf336 Drop extra slash in postgres image url for offline
5d4f8255 Use correct registry for mirroring postgres image to offline
3819b4e1 Update docker images
8ccc7882 Bump contrail docker images
a07d61fb Add default values for qemu max_files and max_proc

Change-Id: I1fa7d348aecb01ba15541ff7319ff5e8f06f0b24