Reporting difference between HTML and TXT

[MasanariHosokawa]

Different behavior of reporting has been found when an assert statement as like assert 3 == 4, which is false and scalar, is used in rule function.
(1) For the output in TXT, it reports as not validated without details of the error in the report. I guess the reason of the False is essential for users.

Summary Report : 
Tested URI : imas:hdf5?user=public;pulse=131024;run=50;database=ITER;version=3
Number of tests carried out : 113
Number of successful tests : 68
Number of failed tests : 45

PASSED IDSs:
+ IDS core_sources occurrence 0
+ IDS distribution_sources occurrence 0
+ IDS nbi occurrence 0
+ IDS pf_active occurrence 0
+ IDS wall occurrence 0

FAILED IDSs:
- IDS core_profiles occurrence 0
	RULE: generic/core_profiles.py:validate_electroneutrality
		MESSAGE: Electroneutrality is not verified
		TRACEBACK: FrameSummary file /home/ITER/hosokam/work/IMAS-IDS_Validator/IMAS-Validator/IMAS-Validator/imas_validator/assets/rulesets/generic/core_profiles.py, line 10 in validate_electroneutrality
		NODES COUNT: 17
		NODES: ['profiles_1d[0]/electrons/density', 'profiles_1d[0]/ion[0]/density', 'profiles_1d[0]/ion[0]/z_ion', 'profiles_1d[0]/ion[1]/density',
...

	RULE: generic/core_profiles.py:validate_z_ion
		MESSAGE: Average ion charge above the summed nuclear charge of ion elements
		TRACEBACK: FrameSummary file /home/ITER/hosokam/work/IMAS-IDS_Validator/IMAS-Validator/IMAS-Validator/imas_validator/assets/rulesets/generic/core_profiles.py, line 28 in validate_z_ion
		NODES COUNT: 24
		NODES: ['profiles_1d[0]/ion[0]/element[0]/atoms_n', 'profiles_1d[0]/ion[0]/element[0]/z_n', 'profiles_1d[0]/ion[0]/z_ion', 
...

- IDS equilibrium occurrence 0
- IDS summary occurrence 0
	RULE: generic/summary.py:validate_source
		MESSAGE: Source node must be filled for any non-empty value node in the SUMMARY IDS
		TRACEBACK: FrameSummary file /home/ITER/hosokam/work/IMAS-IDS_Validator/IMAS-Validator/IMAS-Validator/imas_validator/assets/rulesets/generic/summary.py, line 9 in validate_source
		NODES COUNT: 35
...

(2) Concerning HTML output in same validation above, it is reported as validated and this would be a bug.