mcrypt: Fixed some sprintf buffer overflows

Some potential mcrypt buffer overflows in the commandline tool were fixed,
which could lead to early aborts of mcrypt.
Due to FORTIFY_SOURCE catching such cases, it would have only aborted
mcrypt with a buffer overflow backtrace.

Fixed bugs
bnc#786100
VUL-1: CVE-2012-4527: mcrypt: stack-based buffer overflow via overly long file name
Selected Binaries
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