Close InputStream after use

Found with Kohsuke's file-leak-detector.
Upgrade to testng 6.8.8

Partial changelog:

https://github.com/cbeust/testng/blob/master/CHANGES.txt
Address Checkstyle violations
JCLOUDS-585: Add HP Cloud Block Storage Provider (OpenStack Cinder)
JCLOUDS-617: Use the configured JCE provider in the Cipher payloads
Added the CONTRIBUTING file
Exclude the CONTRIBUTING file from the rat check
Added ConsolesApi extension for openstack-nova
Handle short reads in BasePayloadSlicer

InputStream.read(byte[]) can return fewer bytes than requested.
Specifically ByteSource.concat(ByteSource...).openStream() will only
return as many bytes as the current ByteSource contains.  Thus
ByteSources.repeatingArrayByteSource(byte[]).openStream() will return
short reads despite the byte[] input from its single logical
InputStream.
Default values for aws credential properties

Every project was using undefined properties in their pom.xml.
A default value for test.aws.identity and test.aws.credential was
added.
Avoid impossible UnsupportedEncodingException
Provide descriptive bogus values for properties