installing RedHat 7 on system with Solaris/x86 partition unconditionally overwrites that Solaris partition because partition ID of Soalris is the same as Linux swap. now installer does not ask about which swap partitions to use and unconditionally formats(mkswap)/activates(adds them to fstab) ALL Linux swap partitions. I belive it should provide a list of found Linux Swap (Solaris) partitions and asks about which one(or more) to use as swap.
*** This bug has been marked as a duplicate of 10001 ***