LU-296 Add missing code from auster/yaml port to b1_8

LU-296 Add missing code from auster/yaml port to b1_8

Code related to defining and creating the $TF_FAIL file was missed in
the port of auster and yaml to b1_8. This patch adds the missing
code. Namely:

- Define TF_FAIL in acceptance-small.sh
- add 'touch $TF_FAIL' to the test-framework.sh ERR signal trap

Additionally, the file test for $TF_FAIL variable should be quoted in
acceptance-small.sh and auster.sh. Otherwise, if this variable is not
defined, bash will spit out something like

acceptance-small.sh: line 123: [: too many arguments

Bash variables should generally be quoted whenever they are referenced.
(see http://tldp.org/LDP/abs/html/quotingvar.html).

Signed-off-by: Chris Horn <hornc@cray.com>
Signed-off-by: Yu Jian <yujian@whamcloud.com>
Change-Id: I2071c859d00b8cd8bd423bf9f626b44352456191
Reviewed-on: http://review.whamcloud.com/516
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Tested-by: Hudson