sun-jre: remove circular dependency & minor cleanup

compilers/sun-jre/DEPENDS

@@ -1,4 +1 @@
 depends unzip
-# the download location redirects to HTTPS protocol
-# and we need to make sure wget verifies the certificate
-depends ca-certificates

compilers/sun-jre/PRE_BUILD

@@ -1,15 +1,24 @@
 default_pre_build &&
+
 CURDIR="`pwd`" &&
 cd $SOURCE_CACHE &&
+
 JDK_POLICY=UnlimitedJCEPolicyJDK7.zip &&
+if ! module_installed ca-certificates; then
+   message "${PROBLEM_COLOR}If the following download fails, please make sure you build wget with SSL support and and got ca-certificates installed${DEFAULT_COLOR}"
+fi
 wget -c --header "Cookie: gpw_e24=a" http://download.oracle.com/otn-pub/java/jce/7/$JDK_POLICY &&
+
 JCE_SHA1_VFY='7d3c9ee89536b82cd21c680088b1bced16017253  UnlimitedJCEPolicyJDK7.zip' &&
 JCE_SHA1_TST=`sha1sum UnlimitedJCEPolicyJDK7.zip` &&
+
 if [ "$JCE_SHA1_VFY" != "$JCE_SHA1_TST" ]; then
-message "Bad checksum of $JDK_POLICY file - deleting"
-rm -f $JDK_POLICY
-exit 1
+   message "Bad checksum of $JDK_POLICY file - deleting"
+   rm -f $JDK_POLICY
+   exit 1
 fi &&
+
 cd $SOURCE_DIRECTORY/lib/security &&
 unzip $SOURCE_CACHE/$JDK_POLICY &&
+
 cd "$CURDIR"