Change all python shebangs to python2

ext/mcpat/regression/regression.py

ext/mcpat/regression/verify_output.py

ext/ply/example/classcalc/calc.py

ext/ply/example/newclasscalc/calc.py

src/unittest/genini.py

util/batch/job.py

util/batch/send.py

util/checkpoint-tester.py

util/compile

util/cpt_upgrader.py

util/decode_inst_dep_trace.py

util/decode_inst_trace.py

util/decode_packet_trace.py

util/dram_lat_mem_rd_plot.py

util/dram_sweep_plot.py

util/encode_inst_dep_trace.py

util/encode_packet_trace.py

util/find_copyrights.py

util/memtest-soak.py

util/minorview.py