MFC r318790, r319336

MFC r318790, r319336

r318790:
Fix a buffer overflow in bootparamd(8)

If /etc/bootparams contains a line with an excessively long pathname, and a
client asks for that path, then bootparamd will overflow a buffer and crash
while parsing that line.  This is not remotely exploitable since it requires
a malformed /etc/bootparams file.

Reported by:	Coverity
CID:		1305954
Sponsored by:	Spectra Logic Corp

r319336:
Fix uninitialized variable in bootparamd.c

Restore line that was accidentally deleted in change 318790

Reported by:	Coverity
CID:		1375855
X-MFC-With:	318790
Sponsored by:	Spectra Logic Corp

git-svn-id: svn://svn.freebsd.org/base/stable/10@320780 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f