Fix bug looping non-blocking fifos.

Change-Id: I33dcf575466bfef672af4e113ad692397b5213e9
diff --git a/rsContext.cpp b/rsContext.cpp
index 1a7c5ad..08dd57b 100644
--- a/rsContext.cpp
+++ b/rsContext.cpp
@@ -744,7 +744,7 @@
         return false;
     }
     if (!waitForSpace) {
-        if (mIO.mToClient.getFreeSpace() <= (len + 8)) {
+        if (!mIO.mToClient.makeSpaceNonBlocking(len + 8)) {
             // Not enough room, and not waiting.
             return false;
         }