Automagic scriptlet deps & RHEL6 perms

RPM uses bash --rpm-requires to generate
    Requires: executable(foo)
dependencies.

Sadly, bash --rpm-requires run as non-root on RHEL6 cannot read
certain files any more:

...
+ cp -pr COPYING CREDITS NEWS README docs/ /X/tmp/buildbot-root/usr/share/doc/buildbot-0.7.12
/bin/bash: line 1: /usr/sbin/groupadd: Permission denied
/bin/bash: line 3: /usr/sbin/useradd: Permission denied
/bin/bash: line 5: /usr/sbin/groupadd: Permission denied
/bin/bash: line 7: /usr/sbin/useradd: Permission denied
...

$ ls -al /usr/sbin/{useradd,groupadd}
-rwxr-x--- 1 root root 47540 Jan 12 2010 /usr/sbin/groupadd
-rwxr-x--- 1 root root 94072 Jan 12 2010 /usr/sbin/useradd

The overall effect is harmless, but one WILL get different dependencies
building as root <-> non-root which is likely surprising.