PluginDescription::createIdentifierString not unique ID

Hi there,

According to my findings, PluginDescription::createIdentifierString creates a string that isn’t always unique when applied to a VST: it rather depends on the plug-in location. For example:

OS: Debian Stable with GCC 6.3.0
Juce: 5.1.1

/home/me/audio/vst/mdaAmbience.so      -> VST-mdaAmbience-18fae2d2-6d646141
/home/me/audio/vst-test/mdaAmbience.so -> VST-mdaAmbience-b328b2f6-6d646141

I’ve found a comment in the code (juce_pluginDescription.h) that confirms it:

    /** Either the file containing the plug-in module, or some other unique way
        of identifying it.

        E.g. for an AU, this would be an ID string that the component manager
        could use to retrieve the plug-in. For a VST, it's the file path.
    */
    String fileOrIdentifier;

Wouldn’t this implementation break the “portability” of a VST plug-in or, in other words, the ability to store a plug-in ID for use across different machines?