[security] Security updates

[Lorenzo Iannuzzi]

http://lwn.net/Articles/85282/

Fedora fixes a possible out-of-bounds read in the error message handler
for libpng and libpng10, also a local denial of service in iproute and
stack buffer overflows and directory traversal flaws in lha. 

Trustix fixes multiple apache vulnerabilities and a root exploit in the
kernel.

SuSE fixes multiple vulnerabilities in mc.

Gentoo fixes a denial of service vulnerability in libpng and a
stack-based buffer overflow in exim.
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Ciao e alla prossima!
Lorenzo