Update travis tests

tests/expected_json/old_solc.sol.json.solc-version.json

@@ -22,14 +22,12 @@
             "starting_column": null,
             "ending_column": null
           },
-          "additional_fields": {
           "directive": [
             "solidity",
             "0.4",
             ".21"
           ]
         }
-        }
       ]
     }
   ]

tests/expected_json/old_solc.sol.json.solc-version.txt

@@ -1,5 +1,4 @@
 INFO:Detectors:
 Pragma version "0.4.21" allows old versions (None)
 Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#incorrect-version-of-solidity
-INFO:Slither:/home/travis/build/crytic/slither/scripts/../tests/expected_json/old_solc.sol.json.solc-version.json exists already, the overwrite is prevented
 INFO:Slither:tests/old_solc.sol.json analyzed (1 contracts), 1 result(s) found

tests/expected_json/pragma.0.4.24.pragma.json

@@ -24,14 +24,12 @@
             "starting_column": 1,
             "ending_column": 25
           },
-          "additional_fields": {
           "directive": [
             "solidity",
             "^",
             "0.4",
-              ".24"
+            ".23"
           ]
-          }
         },
         {
           "type": "pragma",
@@ -49,7 +47,6 @@
             "starting_column": 1,
             "ending_column": 25
           },
-          "additional_fields": {
           "directive": [
             "solidity",
             "^",
@@ -57,7 +54,6 @@
             ".24"
           ]
         }
-        }
       ]
     }
   ]

tests/expected_json/solc_version_incorrect.solc-version.json

@@ -24,18 +24,13 @@
             "starting_column": 1,
             "ending_column": 25
           },
-          "additional_fields": {
           "directive": [
             "solidity",
-              ">=",
+            "^",
             "0.4",
-              ".0",
+            ".23"
-              "<",
-              "0.6",
-              ".0"
           ]
         }
-        }
       ]
     },
     {
@@ -60,7 +55,6 @@
             "starting_column": 1,
             "ending_column": 32
           },
-          "additional_fields": {
           "directive": [
             "solidity",
             ">=",
@@ -71,7 +65,6 @@
             ".0"
           ]
         }
-        }
       ]
     }
   ]