i#891: Use /proc/self/exe to find the application path by default
i#891: Use /proc/self/exe to find the application path by default

We still have to use /proc/pid/cmdline when doing early injection, since
/proc/self/exe will point to DR.

I renamed getnamefrompid and get_executable_path so that it clearer
where those implementations are getting their results from.

Fixes issue 891.

Review URL: https://codereview.appspot.com/6488115

git-svn-id: ed337ca7cdb08c0ba29d8fe58632bb7686892c2d@1581 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6

rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio