Bump Security String to 2019-05-05

Implemented:
============
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2019-2043	A-120484087  EoP    Moderate   7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9
CVE-2019-2044	A-123701862  RCE    Critical   7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9
CVE-2019-2045	A-117554758  RCE    Critical   7.0, 7.1.1, 7.1.2, 8.1, 9
CVE-2019-2046	A-117556220  RCE    Critical   7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9
CVE-2019-2047	A-117607414  RCE    Critical   7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9
CVE-2019-2050	A-121327323  EoP    High       8.0, 8.1, 9
CVE-2019-2051	A-117555811  ID	    High       7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9
CVE-2019-2052	A-117556606  ID	    High       7.0, 7.1.1, 7.1.2, 8.1, 9
CVE-2019-2053	A-122074159  ID	    High       7.0, 7.1.1, 7.1.2, 8.0, 8.1, 9

Not Implemented:
================
None

Not Applicable (platform source):
===============
CVE:            References:  Type:  Severity:  Updated AOSP versions:
CVE-2019-2049	A-120445479  EoP    High       9

Change-Id: Ice43d896282a83a63b09b86449bbfd5acd49f5f4