build-pkgs from srpm fail when there is no tarball in srpm

[Ran An]

Brief Description
-----------------
build-pkgs python-rpm-generators fail

Severity
--------
Minor

Steps to Reproduce
------------------
1. git apply patch attached (0001-add-python-rpm-generators-to-build-python3-rpm-gener.patch)
2. build-pkgs python-rpm-generators

Expected Behavior
------------------
The cmd run successfully

Actual Behavior
----------------
Here is the fail log:
"
01:59:23 b4: cat: /localdisk/loadbuild/sidney/starlingx/std/srpm_work/python-rpm-generators/extract_dir: No such file or directory
01:59:23 b4: === CANONICAL_SPEC_GIT=/localdisk/loadbuild/sidney/starlingx/std/srpm_work/python-rpm-generators/gits/python-rpm-generators.spec
01:59:23 b4: === TAR_DIR=python-rpm-generators-6
01:59:23 b4: === PATCH_TARGET_DIR=/localdisk/loadbuild/sidney/starlingx/std/srpm_work/python-rpm-generators/gits/python-rpm-generators.spec/python-rpm-generators-6
01:59:23 b4: === EXTRACT_TARGET_DIR=
01:59:23 b4: Something went wrong
01:59:23 b4: ERROR: srpm_extract_to_git (2491): tarball_extract failed while extracting '/localdisk/designer/sidney/starlingx/cgcs-root/cgcs-centos-repo/Source/python-rpm-generators-6-2.el7.src.rpm'
01:59:23 b4: ERROR: build_dir_srpm (747): failed to extract srpm '/localdisk/designer/sidney/starlingx/cgcs-root/cgcs-centos-repo/Source/python-rpm-generators-6-2.el7.src.rpm'
01:59:23 ERROR: reaper (1312): Failed to edit src.rpm from source at 'b4'
"

Reproducibility
---------------
100%

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
latest code

Last Pass
---------
N/A

Timestamp/Logs
--------------
N/A

Test Activity
-------------
Developer Testing

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/714811

[Ghada Khalil (gkhalil)]

Marking as low priority based on the reporter indicating that this is a minor issue. As far as I know, this doesn't seriously impact stx builds for the larger community of developers

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Don Penney <email address hidden>" on branch: master
Review: https://review.opendev.org/c/starlingx/root/+/714811
Reason: This patch has been idle for more than six months. I am abandoning it to keep the review queue sane. If you are still interested in working on this patch, please unabandon it and upload a new patchset.