pgAdmin 4 commit: Do not send the incomplete definition of a node objec

Do not send the incomplete definition of a node object to the server
instead show proper message.

Tweaked by Ashesh for adding the proper message

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=7a400bacf34fb5dc42bbeabd4171eb4b8041c9af
Author: Khushboo Vashi <khushboo.vashi@enterprisedb.com>

Modified Files
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.../browser/templates/browser/js/messages.js       |  1 +
web/pgadmin/static/js/backform.pgadmin.js          | 63 ++++++++++++----------
2 files changed, 35 insertions(+), 29 deletions(-)