test_gpdb.py: Fix configure command to run w/ options

With `shell=True` in the call to `subprocess.call`, the options to
`configure` were ignored. We don't need the shell and its use is
generally discouraged.
Co-authored-by: NTaylor Vesely <tvesely@pivotal.io>
Co-authored-by: NKaren Huddleston <khuddleston@pivotal.io>

concourse/scripts/test_gpdb.py

@@ -55,7 +55,7 @@ def configure():
                             "--with-python",
                             "--with-libs=/usr/local/gpdb/lib",
                             "--with-includes=/usr/local/gpdb/include",
-                            "--prefix=/usr/local/gpdb"], env=p_env, shell=True, cwd="gpdb_src")
+                            "--prefix=/usr/local/gpdb"], env=p_env, cwd="gpdb_src")
 
 
 def main():