SSTORE/CRCP: use ORTE_WAIT_FOR_COMPLETION with non-blocking receives

During the commits to make the C/R code compile again the
blocking receive calls were replaced by non-blocking
which broke the code. This patch uses ORTE_WAIT_FOR_COMPLETION()
to wait until the non-blocking calls have finished.
SNAPC: use ORTE_WAIT_FOR_COMPLETION with non-blocking receives

During the commits to make the C/R code compile again the
blocking receive calls in snapc_full_app.c were
replaced by non-blocking receive calls.
This commit adds ORTE_WAIT_FOR_COMPLETION()
after each non-blocking receive to wait for the data.
SNAPC/CRCP/SSTORE: remove compiler warnings