Close HTTP response bodies

Fixes

```
[ERROR] unable to parse pkg csvvalidator due to error: Get https://pypi.python.org/simple/csvvalidator: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg csvx due to error: Get https://pypi.python.org/simple/csvx: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg csx due to error: Get https://pypi.python.org/simple/csx: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctable due to error: Get https://pypi.python.org/simple/ctable: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg Csys due to error: Get https://pypi.python.org/simple/Csys: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctd due to error: Get https://pypi.python.org/simple/ctd: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctctwspylib due to error: Get https://pypi.python.org/simple/ctctwspylib: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg cTDMS due to error: Get https://pypi.python.org/simple/cTDMS: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg cTimer due to error: Get https://pypi.python.org/simple/cTimer: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctler due to error: Get https://pypi.python.org/simple/ctler: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctlib due to error: Get https://pypi.python.org/simple/ctlib: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg Ctrax due to error: Get https://pypi.python.org/simple/Ctrax: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctrldaemon due to error: Get https://pypi.python.org/simple/ctrldaemon: dial tcp: lookup pypi.python.org: too many open files
[ERROR] unable to parse pkg ctxvar due to error: Get https://pypi.python.org/simple/ctxvar: dial tcp: lookup pypi.python.org: too many open files

```