Need reviewer: fixes to prtconf for solaris zones and less execs

[Kelly O'Hair]

Need reviewer: fixes to prtconf for solaris zones and less execs

Basically this patch, will be made to openjdk6, 7u4, and jdk8:

diff --git a/make/common/shared/Platform.gmk b/make/common/shared/Platform.gmk
--- a/make/common/shared/Platform.gmk
+++ b/make/common/shared/Platform.gmk
@@ -147,8 +147,8 @@
   endif
   # Suffix for file bundles used in previous release
   BUNDLE_FILE_SUFFIX=.tar
-  # How much RAM does this machine have:
-  MB_OF_MEMORY=$(shell /usr/sbin/prtconf | fgrep 'Memory size:' | expand | cut -d' ' -f3)
+  # How much RAM does this machine have (zones send an error to stderr):
+  MB_OF_MEMORY:=$(shell /usr/sbin/prtconf 2>/dev/null | fgrep 'Memory size:' | expand | cut -d' ' -f3)
 endif

Solaris zones caise prtconf to spit out an error to stderr which we can safely ignore, and this make variable
should be evaluated just once, so the = was changed to a :=.
This only applied to Solaris.

7127104: Build issue with prtconf and zones, also using := to avoid extra execs
http://cr.openjdk.java.net/~ohair/openjdk6/prtconf-zones-execs/webrev/
http://cr.openjdk.java.net/~ohair/openjdk7/prtconf-zones-execs/webrev/
http://cr.openjdk.java.net/~ohair/openjdk8/prtconf-zones-execs/webrev/

-kto