antool: fix handling empty paths

[ldorau]

Empty paths should not be replaced with the CWD during analysis.

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This change is 

[codecov[bot]]

Codecov Report

Merging #399 into master will increase coverage by 0.03%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #399      +/-   ##
==========================================
+ Coverage   77.02%   77.05%   +0.03%     
==========================================
  Files          67       67              
  Lines        8330     8324       -6     
  Branches     1678     1675       -3     
==========================================
- Hits         6416     6414       -2     
+ Misses       1496     1495       -1     
+ Partials      418      415       -3

Flag	Coverage Δ
#ltp_tests	46.45% <ø> (ø)	:arrow_up:
#sqlite_tests	45.16% <ø> (+0.01%)	:arrow_up:
#tests_antool	15.2% <100%> (-0.04%)	:arrow_down:
#tests_posix_multi_threaded	25.04% <ø> (-0.02%)	:arrow_down:
#tests_posix_single_threaded	54.18% <ø> (-0.03%)	:arrow_down:
#tests_preload	44.71% <ø> (+0.03%)	:arrow_up:

Impacted Files	Coverage Δ
src/tools/antool/listsyscalls.py	99.48% <100%> (+0.33%)	:arrow_up:
src/libpmemfile-posix/utils.c	70% <0%> (-1.67%)	:arrow_down:
src/libpmemfile-posix/dir.c	85.74% <0%> (+0.73%)	:arrow_up:

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[krzycz]

Reviewed 3 of 3 files at r1. Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[sarahjelinek]

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Reviewed 3 of 3 files at r1. Review status: :shipit: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable