ASB March 2018, update security string to 2018-03-01

Implemented patches:
==========================================
Media framework
CVE-2017-13248	A-70349612	Critical
CVE-2017-13249	A-70399408	Critical
CVE-2017-13250	A-71375536	Critical
CVE-2017-13251	A-69269702	Critical
CVE-2017-13264	A-70294343	High
CVE-2017-13254	A-70239507	High

System
CVE-2017-13255	A-68776054	Critical
CVE-2017-13256	A-68817966	Critical
CVE-2017-13266	A-69478941	Critical
CVE-2017-13257	A-67110692	High
CVE-2017-13258	A-67863755	High
CVE-2017-13259	A-68161546[2]	High
CVE-2017-13260	A-69177251	High
CVE-2017-13261	A-69177292	High
CVE-2017-13262	A-69271284	High
CVE-2017-13266	A-69478941	Moderate
CVE-2017-13268	A-67058064	Moderate
CVE-2017-13269	A-68818034	Moderate

NOT Implemented, because not relevant
==========================================
Framework
CVE-2017-13263	A-69383160[2]	Moderate  8.x only

Media Framework
CVE-2017-13252	A-70526702	High	  8.x only
CVE-2017-13253	A-71389378	High	  8.x only

System
CVE-2017-13272	A-67110137[2]	Critical  7.x/8.x only
CVE-2017-13265	A-36232423[2,3] Moderate  7.x/8.x only

Change-Id: I7d241a7d859cfadcb9d9aa700cb29e9495dbe902