Commit message not throwing error while commit from git gui (conventional-changelog-archived-repos#79)

* fix(git gui): read commit message from gitgui_editmsg, if required

* addressed review comment, so that user can pass the file name from package.json instead of hard quoting here

Author: krishna63

lib/cli.js

@@ -18,7 +18,11 @@ var getGitFolder = require('./getGitFolder');
 // hacky start if not run by mocha :-D
 // istanbul ignore next
 if (process.argv.join('').indexOf('mocha') === -1) {
-  var commitMsgFileOrText = process.argv[2] || getGitFolder() + '/COMMIT_EDITMSG';
+  var commitMsgFileOrText,
+      gitFolder = getGitFolder() + '/',
+  //GIT GUI stores commit msg @GITGUI_EDITMSG file, so user can pass file name has argument 
+  //if it doesn't exist then we are considering "/COMMIT_EDITMSG" file
+    filename = (process.argv[2] && fs.existsSync(gitFolder  + process.argv[2])) ? process.argv[2] : 'COMMIT_EDITMSG';
 
   var bufferToString = function (buffer) {
     return hasToString(buffer) && buffer.toString();
@@ -28,11 +32,11 @@ if (process.argv.join('').indexOf('mocha') === -1) {
     return x && typeof x.toString === 'function';
   };
 
-  var validate = function (msg, isFile) {
+  var validate = function (msg, isFile, filename) {
     if (!validateMessage(msg)) {
       var incorrectLogFile = (
         isFile
-        ? commitMsgFileOrText.replace('COMMIT_EDITMSG', 'logs/incorrect-commit-msgs')
+        ? commitMsgFileOrText.replace(filename, 'logs/incorrect-commit-msgs')
         : (getGitFolder() + '/logs/incorrect-commit-msgs')
       );
 
@@ -44,6 +48,8 @@ if (process.argv.join('').indexOf('mocha') === -1) {
     }
   };
 
+  commitMsgFileOrText = gitFolder + filename;
+
   fs.readFile(commitMsgFileOrText, function readFile(err, buffer) {
     if(err && err.code !== 'ENOENT') {
       throw err;
@@ -56,6 +62,6 @@ if (process.argv.join('').indexOf('mocha') === -1) {
       : commitMsgFileOrText
     );
 
-    validate(msg, isFile);
+    validate(msg, isFile, filename);
   });
 }