fix: async callback run multiple times in fPutObject

[nomagick]

In some error cases, the async cb function is called multiple(2) times in fPutObject.

minio-js/src/main/minio.js

Lines 1023 to 1033 in 06e4081

	pipesetup(fs.createReadStream(filePath, options), hash)
	.on('data', data => {
	var md5sum = data.md5sum
	var sha256sum = data.sha256sum
	var stream = fs.createReadStream(filePath, options)
	uploader(stream, size, sha256sum, md5sum, (err, objInfo) => {
	callback(err, objInfo)
	cb(true)
	})
	})
	.on('error', e => cb(e))

This causes the async library to generate an exception Error: Callback was already called., crashing the process.

This PR is to fix this issue.

[prakashsvmx]

@nomagick , Thank you. i ran tests locally and looks good.
Please add some details on steps if any to replicate the specific error faced .