Resources: Use path names for ignored dirs

[theotherjimmy]

Description

Ignored directories are collected for the sake of exporters that use
a blacklist-style approach similar to these build tools. This ignore
list will include /filer/<gibberish> when exported from the online
Compiler. This patch fixes that behavoir.

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Docs update
[ ] Test update
[ ] Breaking change

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3628
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8697/

Triggering tests

/morph test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : FAILURE

Build number : 3235
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8697/

[cmonr]

Export falures do not appear to be due to PR.
(Jenkins Nodes dropped)

Will restart when able.

[NirSonnenschein]

/morph export-build

[mbed-ci]

Test : FAILURE

Build number : 3411
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8697/3411

[0xc0170]

Note: This PR is now a part of a rollup PR (#8753).

In order to expedite remaining CI testing, this PR has been bundled into the above rollup PR.

No further work is needed here, as once that PR is merged, this PR will also be closed and marked as merged.

If any more commits are made in this PR, this PR will remain open and have to go through CI on its own.

[cmonr]

Please ignore. I derped.