Fix zlib source code directory name on AT >= 12.0
Fix zlib source code directory name on AT >= 12.0

The checkout of the tarball creates a file that depends on
${ATSRC_PACKAGE_VERID}, but this variable does not exist.

Signed-off-by: Tulio Magno Quites Machado Filho <0e1b3d0765ee75ed64fa2e34822e4949a70a1429@linux.ibm.com>

advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain,advancetoolchain/advance-toolchain