Remove solaris build tag and `contrib/mkimage/solaris

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: 4785f1a7ab7ec857dc3ca849ee6ecadf519ef30e
Component: engine

components/engine/pkg/mount/flags_unsupported.go

@@ -1,4 +1,4 @@
-// +build !linux,!freebsd freebsd,!cgo solaris,!cgo
+// +build !linux,!freebsd freebsd,!cgo
 
 package mount
 

components/engine/pkg/mount/mount.go

@@ -13,7 +13,7 @@ func GetMounts() ([]*Info, error) {
 }
 
 // Mounted determines if a specified mountpoint has been mounted.
-// On Linux it looks at /proc/self/mountinfo and on Solaris at mnttab.
+// On Linux it looks at /proc/self/mountinfo.
 func Mounted(mountpoint string) (bool, error) {
 	entries, err := parseMountTable()
 	if err != nil {

components/engine/pkg/mount/mount_unix_test.go

@@ -1,4 +1,4 @@
-// +build !windows,!solaris
+// +build !windows
 
 package mount
 

components/engine/pkg/mount/mounter_unsupported.go

@@ -1,4 +1,4 @@
-// +build !linux,!freebsd,!solaris freebsd,!cgo solaris,!cgo
+// +build !linux,!freebsd freebsd,!cgo
 
 package mount
 

components/engine/pkg/mount/mountinfo_unsupported.go

@@ -1,4 +1,4 @@
-// +build !windows,!linux,!freebsd,!solaris freebsd,!cgo solaris,!cgo
+// +build !windows,!linux,!freebsd freebsd,!cgo
 
 package mount