MFC r298451,r298452,r298507,r298750:

r298451:

Don't use entry after free in the "already in lists" case

Return with 0 as it isn't an error.

CID: 1006085
Obtained from: Isilon OneFS (part of r493633)

r298452:

Don't try to free string (stack allocated char[])

Fix minor style with warnx call while in the neighborhood

CID: 1009683

r298507:

Fix looking for "UTC" at start of ptr by using strnmp instead of improperly
unrolled equivalent

CID: 1347118

r298750:

Use a better idiom for finding UTC prefixed timezones

Instead of copy-pasting the string literal for "UTC" 3 times and using
strlen, use a static char[3] buffer and sizeof(..).