clean up config tests

Remove tests for config.nyc entries in package.json. Using the fixture
package.json for testing. Clean up config in actual package.json that was there
for test purposes only.

package.json

@@ -34,9 +34,6 @@
       "test/source-map-cache.js",
       "index.covered.js",
       "test/fixtures/_generateCoverage.js"
-    ],
-    "extension": [
-      ".es6"
     ]
   },
   "standard": {

test/src/nyc-test.js

@@ -69,37 +69,21 @@ describe('nyc', function () {
   })
 
   describe('config', function () {
-    it("loads 'exclude' patterns from package.json#config.nyc", function () {
+    it("loads 'exclude' patterns from package.json#nyc", function () {
       var nyc = new NYC({
         cwd: path.resolve(__dirname, '../fixtures')
       })
 
       nyc.exclude.length.should.eql(5)
     })
 
-    it("loads 'exclude' patterns from package.json#nyc", function () {
-      var nyc = new NYC({
-        cwd: path.resolve(__dirname, '../..')
-      })
-
-      nyc.exclude.length.should.eql(19)
-    })
-
-    it("loads 'extension' patterns from package.json#config.nyc", function () {
+    it("loads 'extension' patterns from package.json#nyc", function () {
       var nyc = new NYC({
         cwd: path.resolve(__dirname, '../fixtures')
       })
 
       nyc.extensions.length.should.eql(3)
     })
-
-    it("loads 'extension' from package.json#nyc", function () {
-      var nyc = new NYC({
-        cwd: path.resolve(__dirname, '../..')
-      })
-
-      nyc.extensions.length.should.eql(2)
-    })
   })
 
   describe('_prepGlobPatterns', function () {