Check setName() for null string + fix rsRand().

Change-Id: I5e0042930209861e2eb9acc91380e9473dac0997
diff --git a/libs/rs/rsScriptC_Lib.cpp b/libs/rs/rsScriptC_Lib.cpp
index 23230a6..8a4789a 100644
--- a/libs/rs/rsScriptC_Lib.cpp
+++ b/libs/rs/rsScriptC_Lib.cpp
@@ -76,13 +76,15 @@
 static float SC_randf(float max) {
     float r = (float)rand();
     r *= max;
-    return r / RAND_MAX;
+    r /= RAND_MAX;
+    return r;
 }
 
 static float SC_randf2(float min, float max) {
     float r = (float)rand();
+    r /= RAND_MAX;
     r = r * (max - min) + min;
-    return r / RAND_MAX;
+    return r;
 }
 
 static int SC_randi(int max) {