Fix the dblink _find_libs_to_preserve method to ignore a dropped
non-soname symlink. For example, pam-1.3.1-r1 drops the non-soname
symlink named libpam_misc.so, and we don't want this to trigger
unnecessary preservation of the corresponding library, since the
corresponding libpam_misc.so.0 soname
Fix the dblink _find_libs_to_preserve method to ignore a dropped
non-soname symlink. For example, pam-1.3.1-r1 drops the non-soname
symlink named libpam_misc.so, and we don't want this to trigger
unnecessary preservation of the corresponding library, since the
corresponding libpam_misc.so.0 soname
