perf record: Remove newline character from perror() argument

If we include a newline character in the string argument to perror()
then the output will be split across two lines like so,

    Unable to read perf file descriptor
    : No space left on device

Deleting the newline character prints a much more readable error,

    Unable to read perf file descriptor: No space left on device

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <89e77b54659bc3798b23a5596c2debb7f6f4cf27.1283010281.git.matt@console-pimps.org>
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@felicio.ghostprotocols.net>