lib/oe/utils: Set stderr for host_gcc_version()

lib/oe/utils: Set stderr for host_gcc_version()

Fixed:
$ ln -s /usr/bin/ccache /folk/lyang1/bin/gcc
$ rm -fr tmp/hosttools/ && bitbake -p
[snip]
ERROR: Error running gcc  --version:

It didn't print the error message, now it is:
ERROR: Error running gcc  --version: ccache: error: Could not find compiler "gcc" in PATH

For the error itself, it is because ccache is not in my HOSTTOOLS, so this is
an expected error.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>