[build] fix build exception and revert #9136

[ghooo]

Why I did it

1. Fix Build exception example

2022-02-19T01:54:23.4200556Z ImportError: cannot import name 'soft_unicode' from 'markupsafe' (/usr/local/lib/python3.8/dist-packages/markupsafe/__init__.py)

This is because Jinja2 uses MarkupSafe without specifying an upper limit to the version, MarkupSafe version that was released today removed 'soft_unicode'. So now Jinja2 is complaining.

Related issues:
pallets/jinja#1591
aws/aws-sam-cli#3661

2. Reverts [nvgre] Added YANG model and tests #9136

Fixing build failures in SONiC utils example

One of the errors:

 TestPathAddressing.test_find_ref_paths__ref_is_the_whole_key__returns_ref_paths 

self = <tests.generic_config_updater.gu_common_test.TestPathAddressing testMethod=test_find_ref_paths__ref_is_the_whole_key__returns_ref_paths>

    def test_find_ref_paths__ref_is_the_whole_key__returns_ref_paths(self):
        # Arrange
        path = "/PORT/Ethernet0"
        expected = [
            "/ACL_TABLE/NO-NSW-PACL-V4/ports/0",
            "/VLAN_MEMBER/Vlan1000|Ethernet0",
        ]
    
        # Act
        actual = self.path_addressing.find_ref_paths(path, Files.CROPPED_CONFIG_DB_AS_JSON)
    
        # Assert
>       self.assertEqual(expected, actual)
E       AssertionError: Lists differ: ['/ACL_TABLE/NO-NSW-PACL-V4/ports/0', '/VLAN_MEMBER/Vlan1000|Ethernet0'] != ['/ACL_TABLE/NO-NSW-PACL-V4/ports/0']
E       
E       First list contains 1 additional elements.
E       First extra element 1:
E       '/VLAN_MEMBER/Vlan1000|Ethernet0'
E       
E       - ['/ACL_TABLE/NO-NSW-PACL-V4/ports/0', '/VLAN_MEMBER/Vlan1000|Ethernet0']
E       + ['/ACL_TABLE/NO-NSW-PACL-V4/ports/0']

The VLAN_MEMBER backlink (can be called referrer link or ref link) is not found.

Issue introduced by #9136
I don't know how this PR passed the build system, it should have failed.

Known YANG issue #9312

How I did it

The import to sonic-vlan is breaking the build

    import sonic-vlan {
        prefix vlan;
    }

I am not sure if that's the only issue, so I think reverting the whole PR should be the safer option.

How to verify it

Ran sonic-utils tests locally.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[vadymhlushko-mlnx]

@ghooo, @qiluo-msft
I think, the pull/9136 could be reverted but is more like a temporary crutch. Because using the import in YANG it is a generic functionality.

So, the main issue should be fixed issues/9312.