pmap: print process even if smaps unreadable

pmap: print process even if smaps unreadable

pmap would previously print the process name if
/proc/PID/smaps could be opened, even if subsequent
reads failed.  This actually occurs with other users
PIDs.

Kernel 3.18rc1 introduced a change where the file could
not been opened, meaning pmap -X 1 previously showed
the process name and nothing else but NOW shows nothing
make check failed because of this.

This change prints the process name even before trying to open
the file, returning it to previous behaviour.
Thanks to Vincent Bernat for some analysis.

References:
  https://bugs.debian.org/775624
  https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=29a40ace841cba9b661711f042d1821cdc4ad47c

Signed-off-by: Craig Small <csmall@enc.com.au>