MicrosoftTagTest rewrite image exif fails in some environments

The MicrosoftTagTest test fails on testRewrite() method when supposedly rewritten MicrosoftTagConstants#EXIF_TAG_XPTITLE tag was already defined in another directory.

The problem seems to be that the new value is written into the "Exif" directory, but the original one is in "Root", which is evaluated first while checking test results.