If readonly = true, don't advertise insert/update/delete as supported in capabilities

[jng]

insert/update/delete commands are currently advertised in the OGR provider un-conditionally.

[jng]

In 7645:

Don't advertise insert/update/delete in command capabilities if OGR connection is read-only. Includes unit tests to verify. Fixes #938

[jng]

In 7646:

Merged revision(s) 7638, 7640-7645 from trunk:
Fix incorrect parameter names in CMake build scripts
........
Fix bash-isms in cmake_bootstrap.sh and just inline the contents of setenvironment.sh into this script instead of sed patching and source-ing the patched script
........
Use . instead of source in cmake_build.sh and enable --use-ld-gold switch for linking with gold instead of ld
........
Gracefully handle evaluation of identifiers containing mixed quotes instead of segfaulting. Fixes #946
........
#946: Some explanation as to why the OGR provider test suite was the home for this new test
........
Added OGR unit test to verify spatial and regular filters when combined do play nicely together. Fixes #945
........
Don't advertise insert/update/delete in command capabilities if OGR connection is read-only. Includes unit tests to verify. Fixes #938
........