Fix remaining zgrep(1) wrapper script regressions

[leres]

Summary

Fix short flags without whitespace, e.g:

zgrep -wefoo test

Fix multiple -e flags:

zgrep -e foo -e xxx test

Previously only the last pattern would be used.

Clean up possible leading blank in ${grep_args}.

Update comment: 2.51 -> 2.6.0

Add a test case for the last known zgrep wrapper issue: recursion
(-r) not implemented.

[leres]

• better test for more than one pattern

[bdrewery]

usr.bin/grep/zgrep.sh

106

Somehow this change broke bzgrep -q.

Now:

# bzgrep -q '1 2' /var/log/messages.0.bz2
bzcat: Can't open input file 2: No such file or directory.

Before:

# bzgrep -q '1 2' /var/log/messages.0.bz2

Namely this breaks a Poudriere script with a ton of this:

bzcat: Can't open input file fetch: No such file or directory.
bzcat: Can't open input file it: No such file or directory.
bzcat: Can't open input file -: No such file or directory.
bzcat: Can't open input file please: No such file or directory.
bzcat: Can't open input file try: No such file or directory.

[leres]

I don't have time this week but will definitely look into this next week, including adding a test.