Build - Consolidate bash version checks

There were two checks for bash version, the 2nd was superfluous; this
patch removes the duplicate checks, and shifts the bash version check to
being back after the "are we in bash" check.

Change-Id: I1047a56d7951029f726e8120f8fe04d8d00bbafd
Signed-off-by: STELIX <ssspinni@gmail.com>
Build - envsetup: export ANDROID_BUILD_TOP earlier

Change-Id: I48a0c136bd3bbde28726e3d2b490e952e1ef23e1
Signed-off-by: STELIX <ssspinni@gmail.com>