ver_linux: Process input coming from procmaps that matches libc only

Currently, input coming from /proc/self/maps is split into fields without
checking whether or not it matches libc.so. This is not efficient.
All text processing should only be performed on lines of input that
match libc.so.

Signed-off-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>