compiler: Simplify verifyModelDefinitions()

Refactor `verifyModelDefinitions()` to use the new function
`fixFileExtension` instead of removed `filterValidSourceFiles()`.

lib/compiler.js

@@ -276,25 +276,6 @@ function sortByInheritance(instructions) {
     });
 }
 
-/**
- * Returns matching files with a supported `sourceFile` extension like
- * `.js` or `.coffee`
- * @param {Array} allFiles
- * @param {string} basename
- * @returns {Array}
- */
-function filterValidSourceFiles(allFiles, basename) {
-  var base, ext, validFileType;
-  return allFiles
-    .filter(function(f) {
-      ext = path.extname(f);
-      base = path.basename(f, ext);
-      validFileType = (ext !== '.node') && (ext !== '.json') &&
-      ((typeof require.extensions[ext]) === 'function');
-      return validFileType && (base === basename);
-    });
-}
-
 function verifyModelDefinitions(rootDir, modelDefinitions) {
   if (!modelDefinitions || modelDefinitions.length < 1) {
     return undefined;
@@ -303,22 +284,14 @@ function verifyModelDefinitions(rootDir, modelDefinitions) {
   var registry = {};
   modelDefinitions.forEach(function(definition, idx) {
     if (definition.sourceFile) {
-      try {
-        var fullPath = path.resolve(rootDir, definition.sourceFile);
-        var basename = path.basename(fullPath, path.extname(fullPath));
-        var files = tryReadDir(path.dirname(fullPath));
-        var sourceFile = filterValidSourceFiles(files, basename)[0];
-
-        definition.sourceFile = path.join(path.dirname(fullPath), sourceFile);
-        definition.sourceFile = require.resolve(definition.sourceFile);
-      } catch (err) {
-        debug('Model source code not found: %s - %s',
-          definition.sourceFile,
-          err.code || err);
-        definition.sourceFile = undefined;
+      var fullPath = path.resolve(rootDir, definition.sourceFile);
+      definition.sourceFile = fixFileExtension(
+        fullPath,
+        tryReadDir(path.dirname(fullPath)),
+        true);
+      if (!definition.sourceFile) {
+        debug('Model source code not found: %s - %s', definition.sourceFile);
       }
-    } else {
-      definition.sourceFile = undefined;
     }
 
     debug('Found model "%s" - %s %s',