Remove constants for GosLinux 6.4 (as not supported)

Author: Alexander Lakhin

helpers/constants.py

@@ -269,14 +269,6 @@
         'postgrespro-ent-11': None,
         'postgrespro-1c-9.6': None
     },
-    # may be remove?
-    "GosLinux 6.4": {
-        'postgresql--9.6': None,
-        'postgresql--10': None,
-        'postgresql--11': None,
-        'postgresql--12': None,
-        'postgresql--13': None,
-    },
     # redos-7
     "RED OS 7.2": {
         'postgresql--9.6': None,

tests_install/test_upgrade_minor.py

@@ -62,12 +62,6 @@
     'Debian GNU/Linux 8': {
         'postgrespro-ent-9.6': '9.6.7.1'
     },
-    # maybe remove?
-    'GosLinux 6.4': {
-        'postgrespro-std-9.6': None,
-        'postgrespro-ent-9.6': None,
-        'postgrespro-ent-10': None
-    },
     'GosLinux 7': {
         'postgrespro-std-9.6': None,
         'postgrespro-std-10': '10.6.1',