tests: factor 350 fail=0 initializations into test-lib.sh

Run this command to remove the factored-out "fail=0" lines.
perl -ni -e '/^fail=0$/ or print' $(g grep -l '^fail=0$')
* tests/test-lib.sh: Initialize fail=0 here, not in 300+ scripts.
* tests/...: nearly all bourne shell scripts
Suggested by Eric Blake.

tests/mkdir/p-1

@@ -23,7 +23,6 @@ fi
 
 . $srcdir/test-lib.sh
 
-fail=0
 mkdir --parents "`pwd`/t" || fail=1
 test -d t || fail=1
 

tests/mkdir/p-2

@@ -23,7 +23,6 @@ fi
 
 . $srcdir/test-lib.sh
 
-fail=0
 mkdir --parents "`pwd`/t/u" || fail=1
 test -d t/u || fail=1
 

tests/mkdir/p-3

@@ -30,7 +30,6 @@ mkdir no-access || framework_failure
 mkdir no-acce2s || framework_failure
 mkdir -p no-acce3s/d || framework_failure
 
-fail=0
 p=`pwd`
 (cd no-access && chmod 0 . && mkdir -p "$p/a/b" u/v) 2> /dev/null && fail=1
 test -d "$p/a/b" || fail=1

tests/mkdir/p-slashdot

@@ -23,7 +23,6 @@ fi
 
 . $srcdir/test-lib.sh
 
-fail=0
 
 mkdir -p d1/. || fail=1
 test -d d1 || fail=1

tests/mkdir/p-thru-slink

@@ -25,7 +25,6 @@ fi
 
 ln -s . slink || framework_failure
 
-fail=0
 mkdir -p slink/x || fail=1
 test -d x || fail=1
 

tests/mkdir/p-v

@@ -23,7 +23,6 @@ fi
 
 . $srcdir/test-lib.sh
 
-fail=0
 mkdir -pv foo/a/b/c/d >out || fail=1
 
 diff - out <<\EOF

tests/mkdir/parents

@@ -26,7 +26,6 @@ skip_if_setgid_
 
 mkdir -m 700 e-dir || framework_failure
 
-fail=0
 
 # Make sure `mkdir -p existing-dir' succeeds
 # and that `mkdir existing-dir' fails.

tests/mkdir/perm

@@ -27,7 +27,6 @@ skip_if_setgid_
 
 working_umask_or_skip_
 
-fail=0
 
 #                         parent        parent/dir
 # umask   -m option   resulting perm  resulting perm

tests/mkdir/selinux

@@ -33,7 +33,6 @@ require_selinux_enforcing_
 c=invalid-selinux-context
 msg="failed to set default file creation context to \`$c':"
 
-fail=0
 # Test each of mkdir, mknod, mkfifo with "-Z invalid-context".
 
 for cmd_w_arg in 'mkdir dir' 'mknod b p' 'mkfifo f'; do

tests/mkdir/special-1

@@ -26,7 +26,6 @@ fi
 set_mode_string=u=rwx,g=rx,o=w,-s,+t
 output_mode_string=drwxr-x-wT
 
-fail=0
 tmp=t
 mkdir -m$set_mode_string $tmp || fail=1
 

tests/mkdir/t-slash

@@ -24,7 +24,6 @@ fi
 
 . $srcdir/test-lib.sh
 
-fail=0
 
 mkdir -p dir/ || fail=1
 test -d dir || fail=1

tests/mkdir/writable-under-readonly

@@ -37,7 +37,6 @@ skip_test_ temporarily disabled
 
 # FIXME: define cleanup_ to do the umount
 
-fail=0
 # FIXME: use mktemp
 cd /tmp                                    \
   && dd if=/dev/zero of=1 bs=8192 count=50 \