do not propagate exported bash functions in env

Attempt to mitigate bash vulnerability as well as exposure in target
programs which use the shell to execute commands found in the PATH
(instead of specifying absolute or relative path to command).

http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-6271
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-7169
version 0.10 - proxyexec mitigation for bash vuln

- proxyexec: do not propagate exported bash functions in env