Fix: wrong source directory path returned from ProjectUtils.getSrcDirectories()

ProjectUtils.getSrcDirectories() may return wrong path(s) in case project directory name doesn't match project name.

Note regarding https://github.com/Maccimo/kotlin-eclipse/commit/cb1e020c8c3e265750a3d2c7998907f7e5d6861d#kotlin-eclipse-core-src-org-jetbrains-kotlin-core-utils-projectutils-java-P29 :

In theory classPathResource  may become null in case classpath entry being examined has an absolute path.
Though UI allow entering absolute paths only in aliased form (Java Build Path &rArr; Link Source), i'm unsure we should ignore this case.