import_srpm: check command rpm2cpio|cpio

`rpm2cpio` might not exist on the system, and `cpio` return the error
"premature end of archive" in that case.

This doesn't check if `rpm2cpio` returns an error but it's probably ok
to lean on `cpio` returning an error.

Signed-off-by: Anthony PERARD <anthony.perard@vates.tech>

Author: tperard

scripts/import_srpm.py

@@ -76,7 +76,7 @@ def main():
     print(" extracting SRPM...")
 
     os.chdir('SOURCES')
-    os.system('rpm2cpio "%s" | cpio -idmv' % source_rpm_abs)
+    call_process(['sh', '-c', 'rpm2cpio "%s" | cpio -idmv' % source_rpm_abs])
     os.chdir('..')
     os.system('mv SOURCES/*.spec SPECS/')