[TIMOB-13634] CLI: Reading Android add-on fails if missing manifest.ini file

[ERROR] Application Installer abnormal process termination. Process exit value was 1
c:\Users\Johnny\AppData\Roaming\npm\node_modules\titanium\node_modules\longjohn\dist\longjohn.js:181
        throw e;
              ^
Error: ENOENT, no such file or directory 'C:\Android\add-ons\android-ndk-r7\manifest.ini'
    at fs.openSync (fs.js:338:18)
    at fs.readFileSync (fs.js:182:15)
    at exports.detect.async.series.targets (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\android.js:168:25)
    at exports.visitDirsSync (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\fs.js:99:3)
    at Array.forEach (native)
    at exports.visitDirsSync (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\fs.js:98:5)
    at exports.detect.async.series.cached (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\android.js:167:10)
    at exithandler (child_process.js:538:7)
    at EventEmitter.emit (events.js:99:17)
---------------------------------------------
    at exports.execFile (child_process.js:594:9)
    at exports.exec (child_process.js:481:18)
    at exports.detect.async.series.cached (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\android.js:81:4)
    at async.series.results (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:486:21)
    at _asyncMap (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:185:13)
    at async.forEachSeries.iterate (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:108:13)
    at async.forEachSeries.iterate (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:119:25)
    at _asyncMap (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:187:17)
---------------------------------------------
    at exports.execFile (child_process.js:594:9)
    at exports.exec (child_process.js:481:18)
    at exports.detect.async.series.exec.cwd (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\node-appc\lib\android.js:68:4)
    at async.series.results (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:486:21)
    at _asyncMap (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:185:13)
    at async.forEachSeries.iterate (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:108:13)
    at async.forEachSeries.iterate (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:119:25)
    at _asyncMap (C:\Users\Johnny\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.v20130409124549\node_modules\async\lib\async.js:187:17)

// Create the list of target directories and their properties
afs.visitDirsSync(path.join(sdkPath, 'add-ons'), function(subDir, subDirPath) {
	var manifestFile = path.join(subDirPath, 'manifest.ini');
	if (afs.exists(manifestFile)) {
		var manifest = fs.readFileSync(manifestFile).toString();
		targetDirs.push({
			dirPath: subDirPath,
			name: manifest.match(manifestNameRegex)[1],
			vendor: manifest.match(manifestVendorRegex)[1],
			api: manifest.match(manifestApiRegex)[1],
			revision: manifest.match(manifestRevisionRegex)[1]
		});
	}
});