Revert "testing/testcase: ignore gfortran.so in ldd check"

This reverts commit 8a3c8aa3 because we
still have complaints for binaries that are linked, directly or not, to
libgfortan (e.g. openblas). Adding zlib to the rpath of these binaries
would be annoying.

See slapos@6db91afc

slapos/testing/testcase.py

@@ -204,8 +204,6 @@ def checkSoftware(slap, software_url):
       '*/node_modules/phantomjs*/*',
       '*/grafana/tools/phantomjs/*',
       '*/node_modules/puppeteer/*',
-      # gcc's gfortran runtime is linked against libz and ignores rpath
-      '*/libgfortran.so*',
       # left over of compilation failures
       '*/*__compile__/*',
   ))